080731 6LYG A1 Particular Tunnelling Specification ... - SCATnow

Thames Water Utilities Ltd 

Major Projects 

Thames Tideway Tunnel Programme 

Lee Tunnel 

Main Contract 

Contract No 6LYG/A1 

Section 4 

PT – Particular Tunnelling Specification 

Operating Division 

Waste Water Services 

August 2008

Lee Tunnel, Contract No. 6LYG/A1 

PT – Particular Tunnelling Specification - PT100 

PT100 

PT100.1 

PT100.2 

PT100.3 

PT100.4 

PARTICULAR TUNNELLING SPECIFICATION - INTRODUCTION 

So far as the Specification for Tunnelling may conflict, or be inconsistent, the 

specifications shall prevail in the following order of precedence: 

• Particular Tunnelling Specification 

• Specification for Tunnelling (BTS/ICE 2000) 

• Particular Civil Specification 

• CESWI 

Clause numbers for 'tunnelling' specifications are prefixed with a 'PT', i.e. 

PT112.1.4 etc. For consistency, the 'PT' prefix shall be deemed to apply also to 

all sections and clauses in the Specification for Tunnelling. 

Clauses for the main tunnel 7200mm diameter are prefixed PT2XX, the 3.05 ID 

Abbey Mills Connector Tunnel “TBM and Tunnelling” PT3XX, for the precast 

concrete segmental tunnel linings PT4XX, for the EPDM gaskets to the precast 

concrete segmental tunnel linings PT5XX and for the segmental shaft linnings 

PT6XX. 

This Specification for Tunnelling covers all Tunnelling Works and Segmentally 

lined Shafts within the scope of Works for this Project . 

PT100.5 Diaphragm Walls are specified in the Particular Civil Specification:-PC 3.15. 

PT100.6 

PT100.7 

The Contractor shall refer to the Particular Civil Specification for the requirements 

for all structures not specifically referenced in this specification. 

The Lee Tunnel is a long tunnel drive predominantly in flint laden chalk at high 

water pressures as described in the Geotechnical Baseline Report. The tunnel 

route prevents any direct access to the TBM from the surface. For this reason TW 

considers that the design, performance & operation of the TBM is one of the 

major risk mitigations on the Lee Tunnel. 

This specification should be considered as a MINIMUM requirement. 

Thames Water Utilities Limited August 2008 

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TABLE OF CONTENTS 

PT200 SPECIFICATION FOR NEW TUNNEL BORING MACHINE AND TUNNEL 

CONSTRUCTION – 7200MM MINIMUM NOMINAL INTERNAL DIAMETER 

FOR TUNNEL BETWEEN BECKTON STW AND ABBEY MILLS PS. ...................... 2 

PT201 SUMMARY........................................................................................................... 2 

PT202 REFERENCE STANDARDS ............................................................................... 2 

PT203 DEFINITIONS ...................................................................................................... 2 

PT204 SUBMITTALS ...................................................................................................... 3 

PT205 GENERAL- TUNNEL BORING MACHINE .......................................................... 5 

PT206 MINIMUM REQUIREMENTS FOR TBM TUNNELLING EQUIPMENT............... 6 

PT207 FINITE ELEMENT (F.E.) ANALYSIS................................................................... 6 

PT208 CUTTERS ............................................................................................................ 6 

PT209 CUTTER HEAD ................................................................................................... 7 

PT210 CUTTER HEAD INTERVENTIONS ..................................................................... 8 

PT211 FRONT SHIELD................................................................................................... 8 

PT212 THRUST SYSTEM AND STEERING .................................................................. 9 

PT213 DRIVE SYSTEM .................................................................................................. 9 

PT214 EXCAVATED MATERIAL MUCKING SYSTEM ................................................ 10 

PT215 SEALS................................................................................................................ 12 

PT216 GROUTING SYSTEM........................................................................................ 13 

PT217 SEGMENT ERECTOR....................................................................................... 13 

PT218 ERECTOR BRIDGE........................................................................................... 14 

PT219 SEGMENT MAGAZINE ..................................................................................... 15 

PT220 TBM – LINING INTERFACE.............................................................................. 15 

PT221 CONTROL AND INTERLOCKS......................................................................... 15 

PT222 TBM OPERATION ............................................................................................. 16 

PT223 TBM ELECTRICAL REQUIREMENTS .............................................................. 17 

PT224 GUIDANCE SYSTEMS...................................................................................... 18 

PT225 TAIL SEAL GREASE INJECTION ..................................................................... 21 

PT226 OTHER FEATURES .......................................................................................... 21 

PT227 SPARE PARTS.................................................................................................. 22 

PT228 FIRE PREVENTION – TBM AND BACK-UP..................................................... 22 

PT229 TBM FACTORY TESTING................................................................................. 23 

PT230 QUALITY ASSURANCE .................................................................................... 23 

PT231 QUALITY PLAN ................................................................................................. 24 

PT232 PERSONNEL AND TRAINING.......................................................................... 24 

PT233 TUNNEL HEALTH AND SAFETY ASSURANCE .............................................. 24 

PT234 REGULATIONS. ................................................................................................ 24 

PT235 BORED TUNNEL TEMPORARY FACILITIES................................................... 26 

PT236 TUNNEL BORING MACHINE MAINTENANCE. ............................................... 27 

PT237 GENERAL TUNNELLING CONSTRUCTION REQUIREMENTS...................... 27 

PT238 ELECTRONIC DATA ACQUISITION, VISUALISATION AND REPORTING 

SYSTEM (DAVARS) .......................................................................................... 27 

PT239 GROUTING METHODOLOGY .......................................................................... 29 

PT240 INSTALLATION, MONITORING AND CONTROL FOR SEGMENTAL LINING 30 

PT241 SURFACE DISPLACEMENT MONITORING .................................................... 31 

PT242 DEFECT AND CONDITION SURVEYS ............................................................ 34 

PT243 TEMPORARY ELECTRICITY SUPPLY FOR TUNNEL CONSTRUCTION ...... 34 

PT244 TREATMENT OF ARISINGS............................................................................. 34 

PT245 TBM LAUNCH FROM OVERFLOW SHAFT ..................................................... 36 

PT246 CONSTRUCTION TOLERANCES .................................................................... 36 

PT247 AS-BUILT TUNNEL SURVEY ........................................................................... 36 

PT248 SECONDARY LINING DESIGN AND ISTALLATION ....................................... 37 


Page 1 of 38



PT200 

PT201 

PT201.1 

PT201.2 

PT201.3 

PT202 

PT202.1 

PT202.2 

PT202.3 

PT202.4 

PT202.5 

PT202.6 

PT203 

PT203.1 

PT203.2 

SPECIFICATION FOR NEW TUNNEL BORING MACHINE AND TUNNEL 

CONSTRUCTION – 7200mm MINIMUM NOMINAL INTERNAL DIAMETER FOR 

TUNNEL BETWEEN BECKTON STW AND ABBEY MILLS PS 

SUMMARY 

The work in this Section includes, but is not limited to, providing all labour, 

materials, tools, equipment, and incidentals necessary to construct a 7200mm 

minimum nominal ID finished tunnel (including a primary and secondary lining) in 

accordance with the Works Information and Site Information. 

The work in this Section includes, but is not limited to, the following activities: 

• The provision of a new Tunnel Boring Machine includes, but is not limited to: 

design, manufacture, supply, maintain and testing of a tunnel boring machine 

for the express purpose of constructing TBM excavated tunnels between 

Beckton and Abbey Mills. 

• Boring Tunnel includes, but is not limited to: mining of tunnels, installation of 

pre-cast concrete segmental tunnel lining, temporary tunnel facilities, 

geotechnical monitoring, control of ground loss, settlement and heave, and 

removal and disposal of excavated material. 

• As-Built Tunnel Survey 

This is a performance specification. The Contractor shall be responsible for the 

selection and complete design of the new tunnel boring machine and tunnel 

construction systems. The Works Information, Site Information and GBR provides 

parameters and design criteria for this element of the works. 

REFERENCE STANDARDS 

UK Health and Safety Regulations including but not limited to the Construction, 

Health, Safety and Welfare Regulation 1996, The Confined Spaces Regulations 

1997 and the Approved Code of Practice H.S.E. Document L101. 

Joint Code of Practice for Risk Management of Tunnel Works in the UK published 

by the British Tunnelling Society/Association of British Insurers and the 

International Tunnelling Association/AITES Guidelines to Tunnelling Risk 

Management: ITA Working Group. 

BS6164: 2001 Code of Practice for Safety in Tunnelling in the Construction 

Industry. 

EFNARC (European Federation for Specialist Construction Chemicals and 

Concrete Systems) Specification and Guidelines for the use of Specialist 

Products for Soft Ground Tunnelling. This publication is located at the following 

internet address: http://www.efnarc.org/pdf/SGTSpec.pdf) 

BSEN 12336:2005 -Tunnel Machine Safety Requirements. 

The Groundwater Regulations 1998: “Protection of Groundwater Against Pollution 

Caused by Certain Substances” List One and List Two. 

DEFINITIONS 

TBM excavation: The construction of underground tunnels by mechanical means 

using a tunnel boring machine 

Segmental tunnel lining: Pre-cast concrete segments that are bolted together 

inside the TBM tail shield to form a gasketed, watertight tunnel lining ring. The 

lining shall be designed to withstand both handling loads and all ground and 

external hydrostatic and internal storm water loads. 


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PT203.3 

PT203.4 

PT203.5 

TBM: As used in this Section, the term New TBM means the total system of the 

tunnel boring machine including trailing gear and relevant support equipment, 

materials and any items of plant which are necessary for the sustaining of TBM 

excavation operations all to be designed in accordance with the requirements of 

this Section, all elements of the above shall be new. The TBM shall have the 

ability to apply a sustained and controlled pressure on the tunnel face within a 

pressure bulkhead located behind the face, to form a plenum under pressure with 

the remainder of the tunnel maintained at atmospheric pressure. 

EPBM: An Earth Pressure Balanced TBM with a pressure bulkhead located 

behind the face to form a plenum under pressure. Conditioners can be injected 

through the cutter head and into the plenum to control the quality of the 

excavated material through a screw conveyor in closed or open mode. For the 

construction of this tunnel the EPBM will operate in closed mode at all times, 

unless expressly agreed by the Project Manager. 

SPBM: A Slurry Pressure Balanced TBM utilising a controlled slurry in a 

pressure chamber in the head of the machine to stabilize the face and minimize 

settlement. The resultant slurry, with excavated material, is removed to the Slurry 

Separation plant by pumping. 

PT204 

SUBMITTALS 

PT204.1 The following information shall be submitted to the Project Manager within 28 

days of the award of Contract: 

a) TBM Manufacturer’s Name, Address, and Track Record in Production of 

similar TBMs. 

b) A detailed programme for the design, manufacture and assembly of the TBM 

including the place of manufacture and assembly. The Contractor shall 

arrange regular “Task Force” meetings with the Project Manager and the 

TBM Supplier to develop the TBM design, monitor the manufacture, ensure 

exchange of information, develop TBM transport and assembly requirements 

and meet programme dates. 

c) TBM Concept Plan and Drawings consisting of the following elements: 

i) General Arrangement Drawings from TBM manufacturer 

ii) Proposed TBM type including specifications to meet the minimum 

requirements set out in this document. 

iii) Statement on the technical assistance afforded by the TBM supplier to 

the Contractor during the assembly at the work site and during 

commissioning start up and learning curve until the TBM performance 

requirements have been achieved. 

iv) A statement setting out the training plan for the Contractors proposed 

TBM staff carried out by the in liaison with the Contractor. 

v) Statement of the technical assistance to be afforded by the TBM supplier 

during the assembly of the TBM. 

vi) Type of cutting tools, their wear resistance, expected wear rate and track 

record stating where they have been used on other projects. 

d) Preliminary Quality Plan 

The Preliminary Quality Plan shall indicate the approach and structure that 

the Quality Plan will take with respect to the design and supply of the TBM. 

e) All quality assurance and quality control procedures which are to be used in 

the design, manufacturing, commissioning and maintenance of the TBM. The 

preliminary plan shall cover such issues as, non-destructive testing plans, 

and of steel plate identification, weld testing and procedures. 


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f) Quality assurance audit proposals 

i) A statement detailing the records that will be kept and supplied to the 

Project Manager. 

ii) Inspection and test plans for each activity requiring inspection and the 

level of that inspection. 

g) TBM Detail Plans showing: 

i) Cutters, cutter head and overcut 

ii) Conditioner generation and injection system 

iii) Integrated support pressure control system 

iv) Thrust, steering and drive systems, including main bearing 

v) Shield articulation details demonstrating compliance with the minimum 

radius requirements. 

h) Spoil Treatment 

i) For EPBM, provide details of type of conditioners to be used, mixing 

methods and proposed muck to conditioner ratios, and a description of 

the various conditioners used in anticipated ground conditions for the 

TBM. 

ii) For SPBM, provide details of the slurry treatment plant and operations, 

slurry and conditioner materials and additives to be used. This is to 

include the number of centrifuges that the Contractor proposes to provide 

and the assumptions made in the design of the Separation Plant. 

i) Product Data 

Provide data sheets for materials to be used for tunnel excavation including 

shelf life and handling and storage instructions particularly any polymers shall 

be submitted for acceptance by the Project Manager. 

j) Risk Assessments for the type of TBM selected and associated tunnelling 

method. 

The Contractor shall submit a comprehensive and detailed risk assessment 

for the above. This shall take into account the following: 

i) The strategy for interventions into the cutting head for planned and 

unplanned maintenance or monitoring in high water pressures. 

ii) The ability to undertake major repairs to the TBM. 

iii) The issues associated with transporting spoil within the tunnel and shaft. 

iv) The ability to achieve long term production rates. 

v) Wear resistance of the cutter head, tooling and other wear parts. 

vi) The risk of TBM rolling due to high cutter head torque. 

k) Ground Settlement Control 

i) The contractor shall submit to the Project manager within 28 days of the 

award of Contract, the operation and control features for the TBM to 

minimise subsurface and ground level settlement as described in 

PT206.2. 

ii) A TBM Hazard and Risk Assessment, to be submitted a minimum of 28 

days after award of the Contract. The TBM Hazard and Risk Assessment 

is to include the following: 


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PT204.2 

PT204.3 

PT205 

PT205.1 

PT205.2 

PT205.3 

PT205.4 

PT205.5 

PT205.6 

PT205.7 

• The TBM electrical system (electrical shock and fire, electrical 

equipment fault and damage, loss of power supplies, fire suppression 

systems etc). 

• The TBM Back-up system, leakage of high pressure fluids, close 

location to heat and electrical sources, occurrence of naked flame, 

danger of moving machinery etc). 

• The entry and exit points from the TBM and back-up systems ( To 

include as a minimum:- means of escape during an emergency, 

moving of tunnel lining segments through the TBM back-up on to the 

segment erector, moving of tunnel lining segment on the segment 

erector, dangers to personnel arising from the segment erector, and 

operation of cutter head etc). 

• Access for operation and maintenance for the TBM, including for 

surveying. 

• The slurry discharge circuit (SPBM). 

• The grouting system. 

• TBM assembly and dismantling. 

28 days prior to delivery of the TBM to the Contractor, As-constructed drawings, 

technical documentation and details of the TBM manufacturer’s recommended 

planned maintenance proposals shall be forwarded to the Project Manager. 

Within 28 days, a list of recommended consignment spares that the Contractor 

will retain on Site. The list shall be derived from a risk assessment undertaken by 

the Contractor and agreed with the Project Manager. The risk assessment shall 

identify which parts are likely to wear out, anticipated life-span of the parts and 

level of appropriate spares required on Site. 

GENERAL- TUNNEL BORING MACHINE 

The work of this Section includes, but is not limited to, the following activities: 

supplying a new tunnel boring machine (TBM), as defined in this Section, for the 

express purpose of constructing TBM excavated tunnel in materials of soil types, 

densities, gradations(PSD), strength, abrasivity and hydrostatic pressures 

described in the GBR and Contract Documents. 

The TBM shall be designed to withstand all loads and forces occurring from the 

overburden and hydrostatic pressures and all loads and forces arising from 

operating the TBM, both in normal mode and in modes required to correct 

misalignment. 

The TBM shall be capable of applying a sustained and controlled pressure on the 

tunnel face to maintain surface settlements within the specified limits at all times. 

The bored tunnel lining shall be bolted pre-cast concrete segments fitted with 

EPDM gasket as specified in PT400. 

The selection of tunnel boring equipment and construction methods shall be 

compatible with the ultimate use of the tunnels, the ground and groundwater 

conditions, the depths of tunnels and the proximity of existing structures and 

services. 

TBM and supporting equipment shall be designed in accordance with the 

requirements of CEN standard BSEN 12336:2005 Tunnel Machine Safety 

Requirements. 

Design TBM and backup equipment to negotiate the curves in the alignment and 

meet the specified alignment tolerances as defined in the Contract Documents. 


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PT205.8 

PT205.9 

Diameter of excavated tunnel: to be a minimum of 7200mm ID to match the 

Contractor’s design and to produce minimal over-excavation and least necessary 

clearance. Take into account horizontal and vertical grades to be negotiated. 

Equip TBM with integrated safety systems in accordance with applicable 

regulatory requirements for underground construction equipment and in 

accordance with BS6164 2001 “Safety in Tunnelling in the Construction Industry”. 

PT205.10 All soil conditioning materials, oils, greases, sealing compounds and any other 

material injected into or in contact with the soil, rock or ground water which is 

used during the mining operation shall be compliant with all relevant regulatory 

agencies and the requirements of the Works Information. 

PT206 

PT206.1 

PT206.2 

PT206.3 

PT207 

PT207.1 

PT207.2 

PT208 

PT208.1 

PT208.2 

MINIMUM REQUIREMENTS FOR TBM TUNNELLING EQUIPMENT 

With particular reference to the Works Information and Site Information, the 

requirements as detailed in this Section will not modify or detract in any way 

whatsoever from the Contractor’s sole responsibility for the selection, design and 

operation of the tunnelling plant and equipment. 

The Contractor shall supply, assemble, maintain, operate and remove all 

tunnelling equipment necessary to construct and complete the tunnel in 

accordance with the Works Information and the ground conditions encountered. 

Ground Settlement: - The operation and control features of the TBM shall be 

designed to minimise sub-surface and ground level settlement. Ground loss from 

the TBM boring and tunnel construction shall be limited to a maximum of 1% of 

the excavated volume. The Contractor shall demonstrate in the form of a Method 

Statement the TBM operating principles that shall govern the use of the TBM in 

order to meet these requirements. 

The Contractor shall design the TBM to allow for the replacement of the main 

bearing, rearwards, from within the TBM. 

FINITE ELEMENT (F.E.) ANALYSIS 

The shield shall be designed to withstand all loads and forces occurring from the 

overburden and hydrostatic pressures and all loads and forces arising from 

operating the TBM, both in normal mode and in modes required to correct 

misalignment. 

The design of the structure of the shield body and other important members shall 

be supported by FE method calculations under all loading conditions in graphical 

and numerical form. A Cat 3 check on all critical elements (to be agreed with the 

Project Manager) shall be carried out and the results forwarded to the Project 

Manager for acceptance. 

CUTTERS 

The cutter head shall incorporate: 

Cutting tools appropriate for the expected geological conditions with replaceable 

wear protection. Pick cutters shall have substantial tungsten carbide inserts of 

grade E3 material equivalent to Sinter-HIP or grade B40 and have their exposed 

bodies wear protected with chromium carbide composite plate or similar material. 

Electrical cutter wear indicators shall be fitted to gauge, outer and face pick 

cutters. 

Disc cutters shall be a minimum of 17” dia of a type that will revolve in the mixed 

strata and avoid flats being worn on the tyres, double disc cutters shall be 

considered. Disc cutters shall lead the pick cutters by a minimum of 50mm at the 

face. 

a) Cutter design shall take into account the abrasivity of the ground conditions. 

The cutters shall be hard faced to a design giving best wear resistance. 


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PT208.3 

PT208.4 

PT208.5 

PT209 

PT209.1 

PT209.2 

PT209.3 

PT209.4 

Cutters shall be back loaded such that access for repair and replacement can 

be carried out in safe working condition from within the TBM working 

chamber. 

b) Fixed gauge cutting shall be with disc cutters supported by pick cutters. The 

design shall incorporate a minimum of 6 passes of gauge & semi gauge disc 

cutters. 

c) Rescue tooling shall be incorporated in the outer section of cutter head arms. 

The rescue tools shall be held in reserve and only indexed into use upon 

failure of normal cutters. The rescue tools shall be used to reach a “safe 

haven” where free air conditions prevail to allow tool changing. 

All cutting tools shall be designed to be replaced from the rear face of the cutter 

head. Consideration shall be given to means of improving the work environment 

and reducing the duration of tool changing by use of mechanical aids and access 

ladders. 

The Contractor shall pay particular attention to protection of the moving (rotating) 

elements of the machine against the potentially abrasive nature of the ground. 

The TBM shall be equipped with Chromium Carbide abrasion resistant plating or 

other approved hard facing to all exposed moving surfaces of the TBM, for 

example cutting head and screw conveyor. 

Design components for maximum abrasion resistance and durability. Minimize 

disc cutter wear to the greatest extent possible when not currently in use to 

perform tunnel excavation by such means as designing hubs and bearings to 

allow discs to be readily rotated by hand. 

CUTTER HEAD 

The TBM shall incorporate a soil conditioning system for injection directly onto the 

face. The screw conveyor (if EPBM closed mode) shall also incorporate a facility 

for soil conditioning. Soil conditioning agents shall be bio-degradable and 

acceptable for the excavated materials to be used as a fill. All ports shall be 

independent. 

The TBM shall be capable of excavating through the ground conditions indicated 

in the Works Information and Site Information and geological and geotechnical 

information available to the Contractor without interruption of the excavation 

operations. 

The cutter head structure and bearings shall be rated to absorb the maximum 

forces during tunnelling operations. 

The cutter head shall incorporate the following:- 

a) Rotary fluid coupling for transfer of hydraulic fluids. 

b) Provision to retract the cutter head from the face of the strata without 

rearward movement of the tail shield. 

c) An indexing facility to allow probe and ground treatment drilling through the 

cutter head. 

d) Bi-directional cutting. 

e) The cutter head aperture size shall be designed for all anticipated ground 

conditions as referred to is clause (b) of this section. The proposed aperture 

size shall be included in the tender information provided by the Contractor. It 

shall afford adequate ground support and spoil flow features. A cutter head of 

the open type with a minimum aperture size of 40% shall be provided. 

f) A method of pre-setting the cutter head to index into the desired tool change 

positions without the need to open the air lock entry door. 


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PT209.5 

PT210 

PT210.1 

PT210.2 

PT210.3 

PT210.4 

PT210.5 

PT211 

PT211.1 

g) An adjustable copy cutter with means of detecting the stroke and the arc 

through which it is selected. 

The Contractor shall consider in the design of the TBM a means of ensuring a 

safe method of work for the personnel carrying out all necessary work on the 

cutter head including mechanical aids for the transport of tools and equipment 

into the cutter head. 

CUTTER HEAD INTERVENTIONS 

The Contractor shall submit within 28 days of the award of Contract a Method 

Statement detailing the proposed method for cutter head interventions for 

planned and unplanned maintenance, head inspections and other events. Should 

the use of the TBM compressed air system be considered the Method Statement 

shall demonstrate compliance with following compressed air documents: 

a) Work in Compressed Air Regulations (1996). 

b) Health and Safety Booklet “A Guide to the Work in Compressed Air 

Regulations 1996 – Guidance on Regulations (L96). 

c) Addendum “A guide to the Work in Compressed Air Regulations 1996 – 

Guidance on Oxygen Compression and use of Breathing Mixtures other than 

Compressed Natural Air in the Working Chamber” issued by the Health and 

Safety Executive. 

The Health and Safety Executive have advised the Employer that whilst the 

Regulations are not being revised, a new document combining references b) and 

c) above, along with a revision of the combined text is in preparation and it is 

hoped that this document will be issued by the HSE before the proposed start 

date of this Project. It is understood that the HSE document will set out 

procedures requirements on the Contractor seeking exemptions from the 

Regulations and for the approval by the HSE of the compressed air working 

practices which deviate from those required by the regulations. These could 

include interventions at pressures greater than the present legal pressure limit of 

3.5Bar. With this understanding, it will be the intention of the Employer to hold 

discussions with the Contractor to assess and agree what impact these changes 

will have on the Contractors proposed methodology for interventions at high 

pressures, its impact on the proposed programmes and cost implications. The 

Contractor shall, in order to mitigate any potential delays to the Project and to 

ensure the cooperation and assistance in obtaining required approval from the 

Health and Safety Executive, invite a representative of the HSE to attend any 

discussions held on the issue of working in Hyperbaric Conditions. Preliminary 

discussions will be held between the Employer and the HSE in advance the 

award of Contract to try and secure HSE’s agreement in principle to interventions 

at pressure in excess of 3.5Bar. 

The Contractor will be responsible for obtaining all Regulatory exemptions and/or 

approvals for the proposed methodology and the Project Manager shall be invited 

to attend any meetings held with the Health and Safety Executive (with a 

minimum of two weeks notice). 

The design of airlocks shall conform to BSEN 12110:2002 Tunnelling Machines- 

Air-Locks Safety Requirements (currently being revised). 

The design shall include an effective means of testing for and purging the forward 

chamber of any hazardous gases and ventilating the TBM and back up before 

entry. 

FRONT SHIELD 

The Front Shield shall incorporate a pressure bulkhead designed to withstand all 

operational pressures. 


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PT211.2 

PT211.3 

PT211.4 

PT212 

PT212.1 

PT212.2 

PT212.3 

PT212.4 

PT213 

PT213.1 

PT213.2 

PT213.3 

PT213.4 

A sufficient number of sleeves fitted with shut off valves spaced around the 

periphery for angular ground treatment shall be provided. The arrangement of the 

sleeves shall allow for the formation of a treated zone in the ground 20m diameter 

at a distance of 20m to 30m in front of the TBM cutter head face. This shall 

include the ability to insert freeze pipes through the angular holes to allow 

localised freezing of the ground. 

Provision for multiple probe / ground treatment drilling through the bulkhead to 

include glands and shut off valve shall be provided. This shall include the ability 

to insert freeze pipes through the angular holes to allow localised freezing of a 

ground. 

A collapse detecting device fitted to the front crown area for the detection of voids 

shall be provided. 

THRUST SYSTEM AND STEERING 

Design TBM to provide forward propulsion by thrust cylinders that react against 

the installed segmental lining without damaging the lining and allow segment key 

insertion at pre-determined locations to suit tunnel curves. 

Equip the thrust cylinders with shoes or pads to distribute the jacking forces to the 

lining without damaging the lining. Design the thrust cylinder shoes to be 

consistent with segment and segment joint design while capable of individual and 

synchronized thrust cylinder actuation while limiting the maximum force that each 

thrust cylinder may exert so that linings are not damaged. Thrust cylinders shall 

resist displacements when idle. The control of the shove rams shall ensure that 

only those rams necessary shall be retracted to allow insertion of individual 

segments to prevent rearward movement of the TBM due to hydrostatic 

conditions. 

The TBM shall have a proven anti-roll system. 

The shield shall be articulated, subject to the following: 

a) Design and locate an articulation joint (or joints) as required, to assist 

constructing the tunnel to the theoretical alignment indicated in the Works 

Information and within the specified tunnel construction tolerances. Active 

articulation shall be rated to absorb a minimum of the maximum shove force. 

b) Equip the articulation joint with a seal replaceable from within the TBM to 

prevent the entry of slurry, grout, fines or other foreign material. Provide a 

means for cleaning the articulation joint from inside the TBM to maintain its 

full range of articulation. 

DRIVE SYSTEM 

Provide a TBM having sufficient drive motor power so the machine is not torque 

limited while operating in earth pressure balance mode or slurry mode for any 

ground materials or conditions described in the Geotechnical Baseline Report. A 

torque / speed graph showing constant power characteristics shall be submitted 

to the Project Manager 

Provide capacity to start cutter head with not less than 1.25 times rated full load 

torque. Provide clutches or hydraulic assist for a variable frequency electric drive 

(VFD) or use a variable speed hydraulic drive system. 

The main bearing shall be designed such that it can be removed rearward from 

within the front bulkhead with the minimum of disturbance to other components 

The main bearing shall have a rating of not less than 10,000 hours B10 life based 

upon the assumed loadings defined by the TBM Supplier. The bearing shall be a 

3- row axial, radial and counter axial roller bearing with integral drive gear. The 

Contractor shall submit lifecycle calculations for the main bearing and drive 

pinions against the given load cases for acceptance. As part of the proposal the 


Page 9 of 38



Contractor shall nominate a recognised main bearing supplier and possible 

delivery time mitigation to meet TBM delivery requirements. 

PT213.5 Main drive gearboxes and motors shall have a rating of not less than 10,000 

hours B10 life for the given load cases selected for the main bearing by the 

Contractor. 

PT213.6 

PT213.7 

PT213.8 

To mitigate any risk of gearbox or drive pinion failure causing damage to the main 

bearing gear final drive pinions meshing with the main gear shall have bearing 

supports on each side of the pinion to remove bending moments. The Contractor 

shall submit the details of the gearbox drive pinions and support bearings to the 


Sampling points shall be provided for all lubricants in accessible points. 

TBM drive system shall be bi-directional. 

PT214 

PT214.1 

PT214.2 

PT214.3 

PT214.4 

PT214.5 

PT214.6 

PT214.7 

PT214.8 

PT214.9 

EXCAVATED MATERIAL MUCKING SYSTEM 

If proposing an EPBM, fit and operate earth pressure balance tunnel boring 

machine with a screw conveyor in closed mode or in open mode to remove 

excavated material from the cutterhead chamber. Design the screw conveyor for 

operation in abrasive soil and for efficient replacement from within the tunnel. 

If proposing an EPBM, the screw conveyor shall be designed to maintain the 

required face pressure within the cutterhead chamber and the entrance to the 

screw conveyor. Pressure shall be reduced to atmospheric at the screw exit by 

control of the screw conveyor. The tunnel boring machine shall be capable of 

controlling face pressure to within ± 0.3Bar of the hydrostatic pressure. 

If proposing an EPBM, design the screw conveyor to be capable of being closed 

and sealed against earth pressure at each end. The front of screw conveyor shall 

be located at the base of the pressure chamber and shall project into chamber 

when operating. The screw shall be capable of being withdrawn in order to close 

front bulkhead door for maintenance and removal of obstructions. The design of 

the discharge shall include a system of flow dividers to prevent jamming. In the 

event of a power failure the discharge gate shall be closed by a stored power 

system. 

Fix the exit/outlet end of the EPBM screw conveyor with a pressure lock-out 

device to separate the pressurized ground water and muck from atmospheric 

pressure. 

For EPBM, provide mixing arms within the muck chamber to uniformly condition 

the material in the chamber. 

If proposing an EPBM provide and calibrate, as a minimum, six pressure cells in 

the mucking chamber and a minimum of four pressure cells on the screw 

conveyor all as recommended by manufacturer or as needed to assure accuracy 

of pressure measurements. Both EPBM and SPBM shall utilise the pressure 

gauges to detect water inflow into the mixing chamber to establish prevailing 

ground permeability. 

If proposing an SPBM provide a minimum of four agitator paddles in the suction 

zone of the Working chamber. 

The slurry circuit shall be designed to handle a minimum of: 

a) Solids volume per hour 300 cum. 

b) Total weight of solids volume removed 600 t/hour. 

c) Minimum slurry velocities of 4 m/s to ensure solids remain in suspension. 

The slurry system shall be equipped with: 

a) A means of measuring discharge slurry densities and velocities. 


Page 10 of 38



b) A system which measures the excavated spoil mass and compares with the 

theoretical mass per ring of excavation, to prevent over excavation. 

c) A charge and discharge slurry pipe extension system including the necessary 

pipe handling machines. 

d) Non-return valve system to prevent slurry spillage into the tunnel when 

extending the pipes. 

e) Electrical programmable pump controllers to regulate and maintain the slurry 

circuit pressure. 

f) Bypass circuit and re-circulating controls. 

g) The Contractor shall design the slurry system to cater for anticipated spoil 

including the high strength flints, cobbles and associated abrasive materials. 

h) The Contractor shall carry out a risk assessment based on previous 

experience of similar systems in similar ground conditions to determine the 

location and which components will be subject to high wear and 

maintenance. 

i) The Contractor shall design the slurry main system to facilitate planned 

removal of high wear components with minimum down time. 

j) The Contractor shall have available appropriate spares for replacement of 

components including pumps and pipes. 

k) The Contractor shall prepare and submit his planned maintenance manual to 

the Project Manager. 

l) The Contractor shall provide the design of the proposed Rock Crusher to the 

Project Manager which shall then be tested with samples of flint to 

demonstrate its capability to crush them. 

m) A proven design of rock crusher or crushers shall be provided to reduce flint 

rock to a size of 100mm. The crusher or crushers shall be serviced from the 

rear face of the forward bulkhead in free air conditions. They shall form part 

of the slurry discharge system to ensure that all large rock pieces are 

reduced in size. The rock crushers shall be capable of crushing rocks (flints) 

as described in Contract Documents. The crusher or crushers shall be sized 

on an excavation solids volume of 300 cum/hour of which it can be expected 

75cum/hour may consist of flint pieces. 

n) For SPBM, the TBM shall be designed to work under all conditions described 

in the Works Information and Site Information. This includes the complete 

slurry system required to stabilize the face and drive the tunnel. The slurry 

machine shall be capable of controlling the applied face pressure to within 

0.3Bar of the hydrostatic head. 

o) If proposing SPBM the contractor shall provide a high pressure flushing 

system with the capability to direct flows to improve the agitation of the slurry 

and break up blockages in the area of the aperture of the submerged wall 

and in the area of the entrance to the suction pipes. 

p) If proposing a SPBM the TBM shall be capable of supporting hydrostatic 

pressures of up to 8Bar with an equivalent or greater slurry pressure 

q) Use a conveyor, rail or slurry system for muck transport in the tunnel. Design 

the system for the materials stated in the GBR, including abrasive flint 

chards, chalk fines and Thanet Sands. All proposed systems shall take into 

consideration the designed gradients of the tunnel and the safety of the 

underground personnel. 

r) For all conveyor belt systems, there shall be an audible alarm with a red 

flashing warning light giving the operatives advanced warning that the 

conveyor belt is about to start moving. Emergency stop buttons shall be 


Page 11 of 38



provided at all working points and at frequent intervals along the conveyor 

belt system. Restarting the conveyor shall only be possible from a single 

position and under the control of one person 

s) For SPBM, the design of the slurry treatment plant shall accommodate the 

types and quantities of geological materials anticipated and to remove solids 

from the suspension at a rate such that the slurry treatment does not limit the 

TBM advance rate. The slurry shall be reconditioned or replaced with fresh 

slurry when the slurry properties are unsatisfactory. 

t) For SPBM, the TBM shall be fitted with flow, density and pressure meters in 

the inbound and outbound slurry pipes to: 

i) Monitor the progress of the TBM 

ii) Detect and control conditions in the excavation chamber 

iii) Ensure quality of slurry to the working chamber. 

iv) Detect slurry leakage in the system 

v) To check the actual volume of excavated material against the theoretical 

excavation per ring of advance. 

u) For SPBM the inbound and outbound pipes shall be provided with non-return 

valves to prevent slurry leakage into the tunnel during slurry pipe extensions. 

PT215 

PT215.1 

PT215.2 

PT215.3 

PT215.4 

PT215.5 

PT215.6 

SEALS 

The main bearing sealing system shall be of a proven design capable of 

protecting the bearing life of 10,000 working hours. Provide main bearing seals 

rated for tunnelling conditions and maximum pressure anticipated from the sum of 

all forces acting on the seals simultaneously and all machine operating 

characteristics related to the main bearings. Design the seals for the articulation 

joint, tail shield and probe ports for maximum hydrostatic and earth pressure. The 

sealing system shall be rated to withstand the maximum potential hydrostatic 

pressure as described in the GBR. 

The design shall provide for exchanging both inner and outer sealing systems 

from within the tunnel should failure of the seals occur. 

The main bearing sealing system shall have facilities to monitor its performance. 

Where total loss grease is used for lubrication, cooling and support of the seals a 

means of sampling shall be provided. Where oil is used to lubricate, cool and 

support the seals the TBM shall incorporate a circuit to filter, cool and sample the 

oil. 

The sealing system shall include the flushing of all component parts prior to 

assembly and flushing of the full system 

Shield tail seals shall incorporate a system of wire brushes to seal against 

maximum hydrostatic and cavity grout pressure with due consideration of the 

lining segment design and the influence of lining grouting in seal design. Provide 

a minimum of four rows of tail seals continuously fed with fibrous grease 

whenever the TBM advances. The first fill of the tail seal brushes shall be carried 

out by hand or pump stuffing using a grease of greater density than that used for 

the main tunnelling. 

Tail seals other than the rear seal shall be replaceable from within the tunnel 

during a drive. The Contractor shall provide a method statement before 

completion of TBM design detailing the proposed method for the replacement of 

the Tail seal brushes that shall be submitted for acceptance to the Project 

Manager. 


Page 12 of 38



PT216 

PT216.1 

PT216.2 

PT216.3 

PT216.4 

PT216.5 

PT216.6 

PT217 

PT217.1 

PT217.2 

PT217.3 

PT217.4 

GROUTING SYSTEM 

The Contractor shall provide a computer operated grouting system linked to the 

TBM systems to calculate grout quantities and continuously adjust grout injection 

rate and pressure to ensure it does not exceed the hydrostatic or soil overburden 

pressure. All in accordance with the requirements as specified. 

There shall be provision for continuous pressure grouting the annulus of the 

tunnel linings utilising “A” retarded grout & “B” accelerator mixtures through ports 

in the tail skin. The design of the ports shall allow mixture “B” accelerator to join 

the cement slurry “A” mixture at the point of exit from the tail ports. 

The design shall facilitate their maintenance, ease of water flushing and cleaning 

and replacement by removable plates and pipes as a minimum. 

The TBM shall continuously grout the void behind the shield, as the TBM 

advances, through the tail shield using pipes or channels designed by the TBM 

manufacturer and embedded within the tail shield. For a Thixotropic Gel grout, a 

minimum of 4 delivery pipes shall be provided in the top of the shield from 

shoulder to shoulder. The Contractor shall provide means of clearing or replacing 

blocked pipes within the tail skin by water flushing. Grouting through grout holes 

in the segments will not be acceptable as the primary method of cavity grouting. 

The grouting system shall include 

a) 1-“A” mixture holding tank fitted with agitators with sufficient capacity for 2 

rings. 

b) 1-“B” mixture holding tank with sufficient capacity for 2 rings. 

c) Peristaltic pumps for the supply of grout “A” to the tail skin injection ports. 

d) Peristaltic pumps for the supply of Grout “B” to the tail skin injection ports. 

e) Flow meters for liquid “A” grout. 

f) Flow meters for liquid “B” grout. 

g) Pressure meters for liquid “A” grout. 

h) Automatic injection units. 

Grouting Process 

a) The annulus void between the tunnel lining extrados and the excavated 

ground shall be grouted by means of injection ports located within the tail skin 

of the TBM using a constant pressure grout injection system. 

b) The lines shall be fitted with isolation valves to allow for safe maintenance. 

SEGMENT ERECTOR 

The segment erector shall be compatible with the TBM and lining system to 

ensure safe and efficient segment installation and shall have an appropriate 

factor of safety for the anticipated loads. 

The erector head shall be provided with a vacuum pick up pad for the lifting of the 

segments with positive engagement interlock. A factor of safety 3:1 for lifting the 

heaviest segment shall be applied assuming 0.8 of absolute vacuum. This shall 

be applied to all vacuum devices. 

The erector shall be capable of actuation in the axial, radial, and circumferential 

directions and in the three articulation angles corresponding to the six degrees of 

freedom. Design the erector to grip and erect the segments so that they are 

positioned accurately, so that segments are aligned within the required 

tolerances, so that gaskets on the radial joint are fully compressed, and so that 

no damage or distortion of the segments occurs. 

The segment erector system shall include: 


Page 13 of 38



PT217.5 

PT217.6 

PT217.7 

PT217.8 

PT217.9 

a) Interlock to allow individual or group operation of shove rams for segment 

erection. This shall include safe switching between TBM operator and 

segment erector operator. 

b) Safe lifting alarms. 

c) Vacuum monitoring for segment lifting 

d) Return to pick up segment and automatic location and pick up of segments. 

Provide safe working areas as required to ensure for tunnelling personnel during 

the erection of the segments. 

The erector shall be fitted with a tapered single shear pin to locate into the central 

socket, within the segments. The pin shall be designed to impart the necessary 

cross joint closing force for the proposed gaskets, this shall be designed to 

transmit this force into the central section of the segment by a replaceable plastic 

sleeve to prevent damage to the segment. 

The erector shall be provided with 2 laser pencils that will align with dimples set 

into the segment intrados to ensure location of the shear pin into the segment. 

Operation of any functions using the erector remote control (pendant) shall be 

achieved only by simultaneous selection of an enabling button and the function 

button. 

The TBM segment erector shall be able to retrieve segments for replacement, if 

damage to a segment has been incurred whilst building the ring. 

PT217.10 The erector shall be provided with a means of safe transfer of power cables and 

hoses from static to rotation section by reel, or other approved system. 

PT217.11 

The erector shall be provided with proportional control of main movements. 

PT217.12 The erector shall be provided with a pick up head with axial, rocking and slew 

movements. The rock movement shall be equal to about the “x” & “y” axis of the 

segments. 

PT217.13 All hand held electrical equipment, such as the pendant controls for the segment 

erector, shall be in a watertight enclosures and the control circuit protected by a 

Ground Fault Interrupter Circuit. 

PT217.14 The erector shall be equipped with an integral bearing and seal drive system 

rated for 10,000 hours. 

PT217.15 Vacuum erectors shall be tested prior to the commencement of every shift, by 

holding a segment plate for a minimum of 20 minutes without loss of suction. 

PT217.16 The vacuum system shall be fitted with a pressure sensing device that will detect 

loss of vacuum and prevent operation and lifting of segments, should vacuum fall 

below 0.8Bar. 

PT217.17 

The Contractor shall provide a probe drill facility. 

PT217.18 The erector shall have mounting facilities to hold and direct a probe drill to align 

with angular ground treatment holes and probe holes within the TBM. 

PT217.19 The erector shall be provided with clockwise and anti clockwise rotational 

movements of ± 220º spaced equally about the invert of the tunnel. 

PT218 

PT218.1 

ERECTOR BRIDGE 

The Contractor shall provide details of the erector bridge that demonstrates that 

the design is such that the support of the TBM ancillary equipment shall bridge 

the segment lining installation and grouting areas such that the first bearing on to 

the newly built lining takes account of the grouting time and the designed rate of 

gain of the grout strength. The bridge shall run on rail track supported by brackets 

fastened into the tunnelling. 


Page 14 of 38



PT218.2 

PT218.3 

PT219 

PT219.1 

PT220 

PT220.1 

PT220.2 

PT220.3 

PT220.4 

PT220.5 

PT221 

PT221.1 

PT221.2 

PT221.3 

The erector bridge shall be provided with an articulated towing connection to the 

TBM with load indicating and interlocked features. These features shall include a 

link to the shove rams which will immediately stop the shove should excessive 

loads be transmitted to the towing connection. 

A platform shall be provided for proof grouting directly beyond the tailskin. 

SEGMENT MAGAZINE 

The segment magazine shall include the following features:- 

a) A minimum capacity of one ring. 

b) Be reversible for removal of damaged segments from the ring building area. 

c) The base of the magazine shall be designed such that there is adequate 

access for grouting to the invert plates. 

d) Control of the magazine functions shall be by a trained driver who shall be 

positioned at a fixed station with clear site of movements. 

e) The base structure shall be designed such to allow a clear access walkway to 

the TBM tail area. 

f) There shall be sufficient clearance from the tunnel invert to maintain and take 

oil samples from the segment feeder. 

TBM – LINING INTERFACE 

Concrete segments and associated items shall be designed for anticipated 

ground and water loads and environmental conditions on the completed tunnel. 

The Contractor shall ensure that the segments are compatible with its selected 

construction equipment, means, methods and procedures including, but not 

limited to alignment control, handling, erecting and grouting. 

Maximum ram thrust contact pressure at any point and any time on the lining 

system ram thrust shall not exceed 50% of the segment 28-day compressive 

strength. 

Thrust pads are to be designed such that they shall not damage gaskets or 

segments. 

Design thrust ram shoes to be consistent with the segment design and installation 

procedures, such that they do not introduce eccentric loads to the segments 

Design TBM system to allow complete backfill grouting of the annulus between 

the concrete segments and excavated surface, taking account of hydrostatic 

pressures and overburden loads. 

CONTROL AND INTERLOCKS 

The TBM cutter head shall be prevented from moving at any point during any 

maintenance or entry. An interlock should be provided from the control cabin to 

allow remote inching operation of the cutter head. The Contractor shall establish 

safety procedures, for acceptance by the Project Manager, which will include, 

among other issues, a procedure to ensure that all personnel have evacuated the 

cutter head and front chamber before any movement is undertaken. This 

provision is intended to assist cutter tool changes with local indexing of the cutter 

head. The cutter head drive shall have fail-safe braking system to prevent 

inadvertent movement. 

The shove rams shall be controlled from the main control cabin during the 

excavation cycle and from remote stations during the ring building cycle. An 

interlock shall be provided to prevent duplicate operation of the shove rams. 

All erector load-holding functions shall have a fail safe alarm system. Rotational 

drives shall be fitted with fail safe brakes. 


Page 15 of 38



PT221.4 

PT221.5 

PT221.6 

PT221.7 

PT221.8 

PT221.9 

The segment erector shall be fitted with visual and audibile safe lifting alarms. 

An interlock shall be provided that prevents extension of the shove rams should 

grout delivery through the tail skin be interrupted or blocked. The Contractor shall 

provide a method of automatic data logging and measuring volume and pressure 

of grout injected per tunnel lining ring. 

Condition monitoring of the main bearing the sealing system and main drive 

gearboxes to include oil flow, oil pressure, oil temperature including filter analysis 

and the measurement of metal parts per million on a regular basis to allow 

monitoring of the bearing, sealing system and main drive gearboxes to detect 

contamination and wear. An interlock with the cutter head movement shall be 

provided to prevent use should contamination occur. 

Provide power and torque monitoring. 

Interlocking of cutter head torque to shove rams. 

Provide Cutter tool electrical wear indicators & alarms. 

PT221.10 Monitoring of tail sealer grease delivery, indicating distribution, pressure and 

warnings. 

PT221.11 Monitoring and alarming of grout volume and pressure delivery interlocked with 

advance rate / shove rams – except for final 50mm of the shove 

PT222 

PT222.1 

PT222.2 

PT222.3 

PT222.4 

PT222.5 

PT222.6 

PT222.7 

TBM OPERATION 

The Contractor shall provide an air-conditioned TBM control cabin. This shall 

contain all remote controls and warning indications for the safe operation of the 

TBM and its environment. The operation control cabin should have space for a 

minimum of 4 persons. The controls shall monitor and record the operational 

parameters of the TBM and its systems including the slurry inbound and 

outbound circuits. The cabin shall be equipped with closed circuit television that is 

able to observe the tunnel lining build area, the segment supply magazine and 

area of entry into the gantry of the locomotive and material delivery systems. 

A separate above ground monitoring station shall be provided, it shall duplicate 

the controls within the TBM Control Cabin. The station will have direct links with 

the TBM and will monitor and alarm all spoil volume checks and grout injection 

checks. It shall be supervised at all times during TBM operation by a trained 

dedicated Engineer with authority and means to stop the TBM. 

Performance Requirements 

The Contractor shall design that the TBM is capable of complying with the 

minimum performance factors described in this section. 

Boring Rates of Advance 

The instantaneous rate of advance corresponds to the boring of 1-stroke or width 

of the tunnel lining in 15 minutes. 

Shove Ram Retraction 

Provision shall be made to fast retract and extend individual or groups of rams, to 

allow the starting of tunnel ring erection within 1 minute of completing the shove 

stroke 

Tunnel Lining Supply and Erection 

The duration for the building of one ring of segments is defined as the period from 

engagement of the first segment by the erector to release of the key segment and 

the tightening of bolts. Time = Not greater than 15 minutes 

Rates of Advance - Performance 


Page 16 of 38



PT222.8 

PT223 

PT223.1 

Monitoring the average rates of advance shall be calculated by measuring the 

duration of time to advance twelve successive strokes. The time shall be 

measured from the beginning of the first boring stroke to the placement of the 

final segment. All auxiliary operations, including tunnel segment grouting, tail seal 

greasing, segment feeding and unloading shall be included within the 

performance monitoring. A cyclogramme of tunnelling operations, including all 

operations connected with the tunnelling advance shall be submitted to Project 

Manager. 

Machine Availability 

The TBM shall be designed to achieve a minimum of 95% machine availability 

including planned maintenance periods. Availability shall be the time when the 

TBM and all its associated systems are ready for use and shall be expressed as: 

Availability A= [100 (T-P)] / T. Where T = the time period measured. P = the time 

the machine is unable to work. To maximise TBM availability and performance 

the Contractor ensures that the TBM Supplier provides the following: 

a) Maintenance advice and supervision to the Contractor. 

b) Daily monitoring of equipment and early warning of maintenance 

requirements. 

c) Training of Contractors operatives and maintenance personnel. 

d) A maintenance manual detailing the design life of major components in order 

to establish a spare parts provision regime and to implement a preventative 

maintenance regime. 

TBM ELECTRICAL REQUIREMENTS 

All TBM electrical installations shall comply with the safety and legislative 

requirements in place at the time of the Project duration. 

a) Control equipment shall conform to BSEN 60529 IP65 and, where possible all 

control components should be of the same manufacturer. Any MCB,s 

(Miniature circuit breakers) or MCCB’s (Moulded case circuit breakers) shall 

conform to BSEN60898 with the appropriate fault level rating. 

b) Motors shall be totally enclosed, fan cooled to BS5000 and shall be equipped 

with conventional overload protection and thermisters embedded in the motor 

windings to be used for trip and alarm via the operators console. Electrical 

main drive motors shall be water cooled. 

c) The motor starting methods shall be selected so as to ensure that large 

starting currents are avoided. 

d) All electrical power, control and safety systems shall have a minimum 

moisture ingress protection rating of NEMA 12. All cables in the tunnel shall 

be LSF (Low Smoke and Fume) or LSOH (Low Smoke Zero Halogen) 

sheathed and have the characteristics of a High Oxygen Index, good 

resistance to oil, abrasion and heat. 

e) If the TBM has a high voltage transformer this shall have an over temperature 

alarm and shall include all safety devices as required by the regulatory 

authorities. All electrical power, control and safety systems shall have a 

minimum moisture ingress protection rating of NEMA 12. All cables in the 

tunnel shall be LSF (Low Smoke and Fume) or LSOH (Low Smoke Zero 

Halogen) sheathed. If the TBM has a high voltage transformer this shall have 

an over temperature alarm and shall include all safety devices as required by 

the regulatory authorities. 

f) The TBM and its components shall meet all applicable codes and regulations, 

and all requirements posed by the electric power suppliers and any other 

agencies that have jurisdiction. 


Page 17 of 38



g) Emissions. 

h) The Contractor shall arrange for the complete TBM and back up systems to 

be tested for electrical emissions in conformance with “The Amended 

Consolidated EMC Directive reference EMC89/336/EEC” and issued with CE 

conformance certification. 

PT224 

PT224.1 

PT224.2 

PT224.3 

PT224.4 

GUIDANCE SYSTEMS 

This Section provides guidance on the technical and procedural aspects of an 

integrated, laser-based guidance system for tunnel shields and TBMs. The 

Contractor shall provide a global coordinate TBM Guidance and Control System 

with laser theodolite. This shall be a proprietary manufactured system. 

Technical Aspects 

a) Reference should be made to Works Information for required accuracy and 

tolerance and other matters affecting the operation of the system. 

b) The tunnelling system shall be designed to maintain a clear space for the 

guidance system and laser beam, irrespective of shield or TBM orientation. 

c) The data shall be presented on displays at the underground Machine 

Operators position and at the offices on surface of the Contractor. Facilities to 

download data electronically (for further transmission) and for paper printout, 

independently of the current display, shall be provided. 

Procedural Aspects 

The operation of the guidance system shall be a specific feature of the 

Contractor’s Quality Assurance Plan. This should clearly address: 

a) Definition of responsibility and authority of personnel maintaining and 

operating the guidance system. 

b) Intervals between manual checking of data produced by the guidance system 

(lengthened intervals may be adopted as experience is gained) 

c) Intervals, at which survey control points are to be established, based upon 

tunnel geometry and guidance system characteristics. 

d) The guidance system shall be fully operational whenever the TBM is 

advancing. 

The guidance system shall assist in this by: 

i) Computing the alignment of this plane for the last lining built. 

ii) Computing the corrections required to achieve this plane in the next lining 

to be built. 

iii) For tapered lining rings, the guidance system shall compute the best 

fitting type and orientation of taper lining ring to be built next. The 

guidance system shall be configured to accept data from a minimum of 

four taper ring designs. 



Page 18 of 38



a) The guidance system shall incorporate a non-manual check of the correct 

position the reference laser line at hourly interval. An additional non-manual 

check should be initiated at the commencement of each shift. 

b) The guidance system, including cabling and connectors, shall be capable of a 

sustained, safe operation within the onerous environmental conditions of a 

tunnel under construction, where dust, water, high humidity, varying quality of 

power supply, sustained vibration and repeated shocks are to be expected. 

c) The guidance system shall be self-checking, with redundancy in essential 

components, and shall generate and record appropriate status messages for 

delivery when remotely or locally interrogated and to alert the operator to fault 

conditions immediately as they occur. 

d) Loss of primary power to the guidance system in the tunnel shall not result in 

data loss which would prevent the system self-starting on resumption or 

primary power supply. 


Page 19 of 38



PT224.5 

e) During forward movement of the TBM, the guidance system shall provide as 

a minimum the following real-time data for the TBM, with reference to the 

designed tunnel alignment at the machine head: 

i) Station (chainage) 

ii) Horizontal/line displacement 

iii) Vertical/level/grade displacement 

iv) Left or right lead/yaw at axis level 

v) Overhand or look-up/pitch at axis level 

Main axis rotation 

This information shall be presented in numerical and graphical form, refreshed 

every 20 seconds or faster. 

PT224.6 The accuracy and the limits of each measurement shall be as stated in Table 1 

Accuracy and Limits of Position Measurements. 

Table 1 Accuracy and Limits of Position Measurements 

Data Accuracy (+/-) Limit (+/-) 

Station (chainage) (6mm) (12mm) 

Horizontal displacement (6mm) (6mm) 

Vertical displacement (6mm) (6mm) 

Left or right lead (3mm) (6mm) 

Overhang or look-up (3mm) (6mm) 

Main axis rotation (3mm) (12mm) 

PT224.7 

PT224.8 

PT224.9 

PT224.10 

PT224.11 

The data shall be presented on displays at the underground Machine Operators 

position and at the offices on surface of the Contractor and the Project Manager 

(three displays in all). Facilities to download data electronically (for further 

transmission) and for paper printout, independently of the current display, shall be 

provided at both offices. 

Data shall be recorded in a medium unaffected by primary power loss in a store 

of sufficient capacity to hold the entire tunnels production records. 

The guidance system shall, throughout the forward movement of the TBM, 

compute the correct curve which returns the TBM tangentially to the designed 

tunnel alignment and compute and display the necessary corrections to attitude 

to be applied during the course of the forward movement. This computed data 

may be used directly as input into the control mechanism of the TBM body and 

the excavation and between the tail skin and lining. 

The guidance system should also facilitate construction of the tunnel lining so that 

it follows, and does not bind onto, the TBM. The system shall provide data 

defining the plane of the circumferential joint of the leading edge of the tunnel 

lining with respect to Designed Tunnel Alignment and TBM axis. 







Page 20 of 38



b) Intervals between manual checking of data produced by the guidance system 

(lengthened intervals may be adopted as experience is gained) 

c) Intervals at which survey control points are to be established, based upon 


d) Detection and correction of trends to non-conformance (requiring long-term 

data storage). 

e) Detection and disposal of non-conforming items. 

f) The guidance system must be fully operational whenever the TBM is 

advancing. The guidance system shall assist in this by: 

i) Computing the alignment of this plane for the last lining built 

ii) Computing the corrections required to achieve this plane in the next lining 

to be built. 

PT224.12 For tapered lining rings, the guidance system shall compute the best fitting type 

and orientation of taper lining ring to be built next. The guidance system shall be 

configured to accept data from a minimum of four taper ring designs. 

PT224.13 In making these computations and recommendations, the guidance system shall 

take into account and display clearances between the lining and the TBM tailskin 

and how they will change with the next forward movement. Manual input of 

original clearance data as specified. Locations should be accepted for this 

purpose, provided that the accuracy of measurement is within approximately 

3mm. 

PT224.14 Provide a computer operated grouting system linked to the TBM systems to 

calculate grout quantities and continuously adjust grout injection rate and 

pressure to ensure it does not exceed the hydrostatic or soil overburden 

pressure. All in accordance with the requirements as specified. 

PT225 

PT225.1 

PT225.2 

PT226 

PT226.1 

PT226.2 

PT226.3 

TAIL SEAL GREASE INJECTION 

Tail Seal grease injections shall be automatic and continuous to ensure effective 

filling between the brushes. Injection of grease shall be in accordance with the 

TBM manufacturer’s written requirements, and shall be a positive distribution 

system to ensure even distribution of grease, details of which shall be made 

available to the Project Manager. Tail seal grease shall be fire resistant. 

Tail seal grease shall be compatible with the lining system gaskets and materials, 

shall be inert and fireproof, and shall not contaminate the surrounding ground or 

groundwater and shall not in any way cause the long term deterioration of the 

lining concrete, the joint connector, the gaskets, seals or joint packers. The 

design shall facilitate their maintenance and replacement. 

OTHER FEATURES 

Provide method to test for the presence of hazardous or explosive gas in 

accordance with Health and Safety regulations requirements. 

Provide an environmental monitoring system that detects levels of potentially 

hazardous gases. Systems shall be arranged with adjustable limits and shall 

have a first level warning signal and a second level with automatic shut off of 

tunnelling equipment in accordance with Health and Safety Regulations 

requirements. Gases to be monitored shall include methane, oxygen, hydrogen 

sulphide, carbon dioxide and carbon monoxide. 

The Contractor shall supply Calibration Test Certificates for gas detection system, 

pressure cells in excavation chamber and screw conveyor, TBM guidance system 


Page 21 of 38



PT226.4 

PT226.5 

PT226.6 

PT227 

PT227.1 

PT227.2 

PT227.3 

PT228 

PT228.1 

and grout pressure gauges. Certificates to be updated in accordance with the 

manufacturers recommendations. 

In order to provide a clean environment for placing of the invert segment plate, 

the Contractor shall take appropriate measures to keep the shield area free from 

water and spoil material. Pumping facilities in the shield area of the TBM shall be 

designed to allow sufficient space for the equipment proposed. 

Only TBM synthetic hydraulic oils HFDU (biodegradable, fire resistant, 

polyesters) shall be used. All oils shall be approved by the TBM manufacturer. 

The Contractor shall provide foams, polymers, bentonite or other conditioners as 

required for stabilizing the tunnel face and maintaining the required pressure until 

discharge from the screw conveyor/slurry discharge pipes under all conditions 

described in the Works Information and Site Information. All conditioners shall be 

biodegradable, inert and conform with Environment Agency requirements in List 1 

and 2 of the Groundwater Regulation 1998, unless otherwise agreed with the 


SPARE PARTS 

Spare parts or maintenance materials to be stored on site shall include all items 

with lead in times greater than two days including: 

a) Parts and materials listed in the TBM manufacturer’s recommended spares 

list and maintenance plan. 

b) One complete set of excavation tools (discs, rippers and other cutters. One 

set consists of a complete replacement of all tools on the cutter head. 

c) Hydraulic rams, hydraulic hoses and components. 

d) Seals, o-rings and gaskets. 

e) Electrical and Mechanical components. 

Major spare parts to be stored off-site. 

Have one spare main bearing assembly, seals(bull gear), and one spare main 

drive motor stored off-site and vested to Thames Water and available from the 

TBM manufacturer for prompt replacement of the corresponding parts provided 

with the TBM. These spares shall be identified and available for the duration of 

the TBM excavation. 

FIRE PREVENTION – TBM AND BACK-UP 

Subject to the conclusions of the hazard assessment, the TBM and back up 

systems shall be provided with: 

a) A fire hazard assessment, which will address all potential fire sources, shall 

be carried out to the acceptance of the Project Manager. 

b) The fire suppression system shall be compatible with the hazard assessment. 

c) Electrical cabinets shall be fitted with a manually operated fire suppression 

system. 

d) Emergency plunger buttons at suitable locations to activate a fire alarm. 

e) Hand held extinguishers provided with colour coded covers in suitable 

locations. 

f) A means of rapidly shutting off fresh air ventilation to the tunnel face, after the 

area has been evacuated. 

g) Permanent notices giving emergency procedures, in the event of fire, placed 

in suitable locations. 

h) Operators and training manuals for use by the Contractor. 


Page 22 of 38



i) Hydraulic hoses shall comply with BS EN 853. / ISO 1436. The hose covers 

to be flame retardant and to conform to the requirements of USMSHA. 

j) Gas monitoring for oxygen deficiency, CO2, CO, H2S, NO2, SO2 and CH4 . 

k) Water mist screen to be positioned at the rear of the Back-Up System. 

l) Low density foam generators to be sited at high fire risk areas with automatic 

operation in the event of fire. 

m) Essential services shall be protected so that they remain operable during all 

tunnelling operations for a period of 1 hour. These essential Services are: 

i) Emergency power supplies. 

ii) All fire suppression systems. 

iii) TBM emergency lighting. 

iv) Environmental monitoring systems 

v) All controls and tunnel communications. 

vi) The security of the air supply and control systems to the man lock shall 

remain operable in all emergencies, particularly in the case of fire. 

PT229 

PT229.1 

PT229.2 

PT229.3 

PT230 

PT230.1 

PT230.2 

PT230.3 

PT230.4 

TBM FACTORY TESTING 

The Contractor shall submit, at least 30 days prior to the commencement of any 

factory tests, a test schedule and programme for the TBM and back-up system. 

The Contractor shall allow in his bid for the direct expenses, travel, and 

accommodation for the attendance by the Project Manager at the factory tests. 

The TBM shall be tested in accordance with the manufacturers recommendations 

and a certificate of confirmation of compliance with the requirements of this 

Section, together with a copy of the test results, shall be signed by the Contractor 

and the TBM manufacturer and shall be forwarded to the Project Manager prior to 

the TBM being delivered to the Site. 

The test shall include a demonstration mock up of the concrete segment erection 

system, using the precast concrete segments as proposed for the project. 

QUALITY ASSURANCE 

The Contractor shall operate a Quality Management system in accordance with of 

ISO9001, 9002 & 9003 Quality Assurance Requirements. The Quality 

Management system shall include procedures for design, manufacturing, testing, 

commissioning and maintenance of the TBM. It shall provide the results of all 

specified tests and inspections to the Project Manager. Periodically during the 

manufacturer of the TBM the Employer may conduct compliance audits relating to 

the design and supply of the TBM. The Contractor shall provide suitably qualified 

staff to assist the audit team 

TBM Manufacturer: The proposed TBM manufacturer shall be a recognised 

commercial TBM manufacturer with no less than 5 years of successful 

experience in the design and manufacture of TBMs of the type proposed by the 

Contractor. 

For his works the Contractor shall use only qualified and suitably experienced 

persons in the following key positions:- Contract Manager, Construction Agent, 

TBM Mechanical Foreman and Electrical Foreman and TBM Operators. The 

Contractor shall submit the names and CVs of those key persons he proposes to 

use on this project. 

The Contractor shall arrange for a Technical Representative from the TBM 

manufacturer or an approved independent specialist, who is experienced in the 

assembly, operation and repair of TBMs, to be present for the duration of the 


Page 23 of 38



assembly of the TBM in the Launch shaft, as well as for start-up and operation of 

the TBM for the first 1000mtrs of the tunnel drive. The technical representative 

shall certify in writing to the Project Manager that the TBM, as assembled, meets 

the Specified requirements. 

PT231 

PT231.1 

PT231.2 

PT232 

PT232.1 

PT232.2 

PT232.3 

PT233 

PT234 

QUALITY PLAN 

Within 4 weeks from award of Contract the Contractor shall submit a detailed 

Quality Plan based upon the Preliminary Quality Plan provided as a submittal 

under PT204. 

The Quality Plan shall be regularly updated to reflect any changes made to the 

procedures. 

PERSONNEL AND TRAINING 

The Contractor shall ensure that all key personnel who are responsible for 

driving, maintenance and controlling the TBM, including any specialist for the 

TBM computer systems, have received the necessary training in the duties that 

they are required to perform. Such training shall include emergency procedures. 

The Contractor shall provide and maintain a complete register of the names of 

persons, and their duties, responsible for the operation of the TBM, who have 

completed the appropriate training to an accepted standard. 

The Contractor shall provide a foreman fitter on site for the duration of the 

tunnelling works. A fitter and electrician shall be provided for every shift. The 

Contractor shall provide the Project Manager with copies of the curriculum vitae 

for all fitters and electricians. 

TUNNEL HEALTH AND SAFETY ASSURANCE 

As part of the Contractor’s Safety programme the Contractor shall produce a 

Tunnel Specific Safety Statement within 3 months of contract award detailing the 

precautions to be implemented to protect personnel working in the tunnel from 

the construction methodology risks associated with tunnelling at the designed 

gradients and long section. These shall include but not limited to: 

• Risk of runaway trains and derailments. 

• Tunnel inundations. 

• Control of water and standby provisions. 

• Temporary Tunnel Ventilation System. 

• Emergency evacuation of tunnel. 

• Fire precautions including the role of the appropriate fighting authority in the 

event of a tunnel fire. The procedure shall need to address all possible fire 

location and tunnel length scenarios. 

• Management of rail and pedestrian movements in the tunnel. 

REGULATIONS 

The design and manufacture of the TBM and back up systems shall comply with 

all relevant regulations and codes of practice including, but not limited to those 

described below. The Contractor shall ensure he always uses the latest published 

version of any standard that relates to safety. These shall include but are not 

limited to: 

• Section 6: Health and Safety at Work Act. 

• A Guide to working in Compressed Air 1996 guidance on oxygen 

decompression. 


Page 24 of 38



• Ventilation COSHH 

• Acoustics Noise emitted by machinery ISO/DP 9244:1986. 

• The Construction (Design and Management) Regulations 2007. 

• The Management of Health and Safety at Work Regulations 1992. 

• The Construction Health, Safety and Welfare Regulations 1996. 

• The Personal Protective Equipment at Work Regulations 1992. 

• The Control of Substances Hazardous to Health Regulations 1994. 

• The HSE Occupational Exposure Limits EH40/1996 (Updated Annually). 

• BS 5750 (BSEN ISO 9001, 9002 & 9003) Quality management and quality 

assurance standards. 

• BS EN 50073 Selection, installation, use and maintenance of apparatus for 

the detection and measurement of industrial gases. 

• BS 5345 Parts 1 to 8 inclusive, Selection, installation and maintenance of 

electrical e in potentially explosive atmospheres, where applicable. 

• BS EN 50054 to 50058 1991. Electrical apparatus for the detection and 

measurement of combustible gases general requirements and test methods. 

(This series of British and European unified standards replaces BS 6020 

parts 1 to 5. “Instruments for the detection of combustible gases.” 

• BS EN 60079-25:2004 Electrical apparatus for potentially explosive 

atmospheres, where applicable. 

• Supply of Machinery (Safety) Regulations 1992-Schedule 3, clauses 1.5.8, 

1.5.9, 1.7.4, 2.2 and 3.6.3; 

• Supporting [“C” Type Safety] Standards-Noise and Vibration Test Codes 

information required by manufacturers claim of “CE” Conformity. 

• BSEN 457 Safety of Machinery - Auditory danger signals - general 

requirements, design, design and testing. 

• BSEN 60034-9 Rotating Electrical Machines -Noise Limits. 

• BSEN 45014 General criteria for supplier’s declaration of conformity. 

• BS EN 981 Safety of machinery-System of Danger and Non Danger signals 

with sound and light. 

• BSEN 61310-1 Safety of Machinery-Indicating, marking and actuating 

principles; part 1 Visual, audible and tactile signals. 

• BS EN 1012 Compressors and vacuum pumps; Safety requirements. 

• ISO 4871 Acoustics-Noise labelling of machinery and equipment. 

• ISO 4872 Acoustics-Measurement of airborne noise emitted by construction 

equipment intended for outdoor use-Method of determining compliance with 

noise limits. 

• ISO 6394 Acoustics -Measurement of airborne noise emitted by earth moving 

machinery-Operators position-stationary test condition. 

• ISO 6395 Acoustics-Measurement of exterior noise emitted by earth moving 

machinery-Dynamic test conditions. 

• ISO/TR 11688; Parts 1 & 2: acoustics-Guidelines for the design of low noise 

machinery and equipment. 


Page 25 of 38



• ISO/DRT 11690; Parts 1,2 & 3: Acoustics-Recommended practice for the 

design of low noise workplaces containing machinery. 

• Noise at Work Regulations 1989 (refer to regulation12). 

• Section 2 HSW/HS (G) 88, Hand-arm vibration; 

• BS 6841:1987; Measurement and evaluation of human exposure to whole 

body mechanical vibration and repeated shock. 

• BS 6842: 1987; Measurement and evaluation of human exposure to vibration 

transmitted to the hand. 

PT235 

PT234.1 

PT234.2 

PT234.3 

BORED TUNNEL TEMPORARY FACILITIES 

The Contractor shall provide, operate and maintain for the duration of tunnelling 

construction a temporary ventilation system, which conforms to the Health and 

Safety requirements. The equipment shall be adequate to maintain sufficient 

supply of fresh air in underground work areas. 

a) Mechanical ventilation systems shall not be removed without the acceptance 

of the Project Manager. 

b) As a minimum, when the excavations are occupied by workers, the ventilation 

system shall be designed to deliver fresh air at a volumetric flow rate equal to 

20mtrs per minute times the cross-sectional area of the tunnel. A higher 

volumetric flow rate shall be provided if necessary 

c) Power to the main ventilation system shall not be interrupted in the event of 

an alarm of the air monitoring system. 

d) Advance of the ventilation system shall be made a regular part of the normal 

tunnel excavation cycle. 

e) Temporary Tunnel Lighting System: The Contractor shall provide a temporary 

lighting system in the tunnel which conforms to the requirements of 

BS6164:2001“Code of practice for safety in tunnelling in the construction 

industry”. Lighting in the tunnel shall extend the full length of the tunnel and 

not be less than that required for safe working and access. An alternative 

source of power and emergency lighting system shall be provided to allow 

emergency securing operations and safe evacuation in the event of a primary 

power failure. An adequate number of hand lamps shall be located at key 

points underground. 

f) Temporary Personnel Walkway: The Contractor shall provide walking access 

in the tunnel at all times. This shall have a firm, level, slip- resistant and 

continuous surface and shall be suitable for use in emergencies. 

g) Temporary Locomotive Track: The track should be properly supported and 

secured against displacement in the tunnel. The entire length of the track 

shall be examined not less than once a week and the results of this 

inspection shall be forwarded to the Project Manager. Defects shall be 

recorded and remedial action will be promptly implemented when identified. 

h) Temporary Pumping: Provide intermediate pumping stations and reserve 

pumping capacity at the any point of the tunnel as required to remove 

groundwater inflows and construction water. 

i) Fire Extinguishers: Fire extinguishers shall be provided at a minimum every 

500 metres of the running tunnels. They shall be maintained in accordance 

with the manufacturer’s recommendations. 

Smoking Policy 

There shall be no smoking in the tunnel. 

Breathing Sets 


Page 26 of 38



Approved emergency breathing apparatus or approved oxygen self-rescuers as 

appropriate shall be provided and kept with all persons visiting or working in the 

tunnel for the duration of their time in the tunnel. All such equipment shall be 

regularly maintained in accordance with the manufacturers recommendations, 

records shall be kept in the Contractors site office and made available for 

inspection by the Project Manager. 

PT236 

PT236.1 

PT236.2 

PT237 

PT237.1 

PT237.2 

PT237.3 

PT237.4 

PT238 

PT238.1 

TUNNEL BORING MACHINE MAINTENANCE. 

The Contractor shall monitor and analyse lubricants in critical areas of the 

tunnelling equipment on a weekly basis. This shall be performed by an 

Independent Laboratory to identify the presence of any pollutants. Critical areas 

shall include all major sealing systems, main bearing, final drive gear, hydraulic 

systems and motor gear boxes. The results of the analysis shall be forwarded to 

the Project Manager upon receipt together with any proposals for remedial action 

where pollutants have been identified. 

The Contractor shall forward to the Project Manager within 3 months of contract 

award details of proposals for the routine periodic preventative maintenance 

programme that shall be adopted during the tunnelling operation. A nominated 

person shall be responsible for ensuring compliance with all preventative 

maintenance procedures. 

GENERAL TUNNELLING CONSTRUCTION REQUIREMENTS 

Perform tunnel construction to minimize movement of ground in advance of, 

around and above the tunnel; to control water and water inflow and attendant soil 

transport; and to minimize settlement, subsidence and heave of the ground 

surface, structures, and utilities above and close to the tunnel for ground 

conditions that are to be encountered as described in the Works Information and 

Site Information. Conduct tunnelling operations in a controlled manner so that 

settlement action levels are not reached. 

Unstable Conditions Procedures: Whenever there is a condition likely to 

endanger the excavation or adjacent structures, notify the Project Manager 

immediately and perform work on a 24-hour a day basis, including weekends and 

holidays, until such condition is resolved and eliminated. Briefings are to be given 

to mining gangs prior to tunnelling on the procedure for dealing with unstable 

conditions. 

Maintain clean working conditions inside the tunnel by continuously and promptly 

performing housekeeping to remove muck and grout spills, rubbish and other 

debris. 

A driving parameters check sheet shall be provided daily to the mining crews to 

allow the drive to be controlled and monitored. 

ELECTRONIC DATA ACQUISITION, VISUALISATION AND REPORTING 

SYSTEM (DAVARS) 

The Contractor shall supply a computer-based Data Acquisition and 

Visualisation System’ DAVARS which can be used for the preparation and 

distribution of reports, This system shall fulfil the following main specifications. 

Extent and scope of DAVARS 

The DAVARS shall handle data and digital pictures, as minimum but not limited 

to, of: 

• The Tunnel Boring Machine (TBM), 

• The tunnel mucking system, 

• The reporting system, as agreed with the Project manager for Ring Reports 

and Shift Reports 


Page 27 of 38



PT238.2 

PT238.3 

PT238.4 

PT238.5 

PT238.6 

PT238.7 

PT238.8 

• The Quality Management / Quality Assurance (QM/QC) for the tunnelling 

process, including its reporting system (Non-Conformance Reports and 

Remedial Work Reports, etc.), 

• The ring erection data, 

• Ground surface, ground settlements, 

• The alignment data, 

• Display of the geology along the alignment, and statistic evaluations. 

The data shall be transferred automatically, into the DAVARS. 

The DAVARS shall allow the Employer and his representatives to execute by 

themselves, visualisation in any display combination of sensors and data labels. 

Real time data input 

a) One set of all data generated by the TBM, the mucking systems, tunnel 

guidance system and, if applicable, automated surveillance systems, shall be 

read into the data base at least every ten seconds. 

b) This data shall be transferred directly by the equipment’s PLC and must not 

be handled through a secondary data system. 

c) Procedures, which are controlled and recorded in intervals longer then one 

hour, shall be introduced into the data base manually by the Contractor on 

the same day. 

Accessibility of DAVARS 

a) The data shall be stored into a project data base, accessible through Internet 

by the Employer and his authorised representatives at any time. 

b) The DAVARS shall be kept operational for the Employer from TBM 

installation in the launch position throughout the project until final acceptance 

and financial closure of the Project. 

c) The Employer will receive one electronic copy of the database at the end of 

the Project. 

Further Functions of DAVARS 

a) The DAVARS shall allow printing and emailing of the graphs and reports at 

any work place while being logged-in. 

b) The DAVARS shall allow for applying active triggers to arbitrary parameters 

and connecting the triggers with message functions. Passing the set trigger 

level shall initiate a notification by email to selected individuals. 

Real Time Data Management 

The Contractor shall provide Shift Records using semi- automatic Real Time Data 

Loggers software for on-line display and in hard copy to the Project Manager, 

detailing work performed except where otherwise allowed or accepted herein, 

and integrated with requirements specified elsewhere for erection of precast 

segments, cavity grouting, and permeation grouting including: 

a) Date, location, shift and beginning and ending face station. A manual check 

of the TBM face location shall be conducted on a weekly basis. 

b) List of personnel by name, classification, and function working that shift. 

c) List of the number and type of equipment, including amount of and reason for 

any idle or down time. 

d) List of all materials used in the work. 

For every TBM shove or stroke: 


Page 28 of 38



PT238.9 

PT239 

PT239.1 

PT239.2 

PT239.3 

PT239.4 

a) Description of soil or bedrock materials being excavated, including boulders 

and volume of excavated materials using methods as mutually agreed when 

not otherwise specified. 

b) Description of delays and down time longer than 10 minutes, including reason 

for delay. Include maintenance records identifying the component, 

component position or number and reason for replacement. 

c) Description and locations of water inflows, ground loss and other events. 

d) Cutter, pick teeth and muck system component changes, including time and 

date of replacement, cutter or component position or number, and reason for 

change. 

e) Rates of advance for each hour. 

f) Hours of actual machine operating time for each shift. 

g) Max thrust pressure for each shove. 

h) Ring number at start and end of each shift. 

i) Type, manufacturer and producer name and number of all ground 

conditioners used on each shift. 

j) Volume and pressure of grout pumped behind precast segments on each 

ring. 

Results of quality control tests including: 

a) Volume of conditioner used as applicable for EPBM operations 

b) Volume of slurry and slurry density, as applicable for SPBM operations 

GROUTING METHODOLOGY 

Submittals 

a) Contractor shall submit to the Project Manager, within 28 days of award of 

Contract, for review and acceptance, a programme showing the methods and 

sequencing of placing primary and proof grouting 

b) The Contractor shall submit to the Project Manager for acceptance within 60 

days of the award of Contract a detailed Method Statement of the grouting 

procedures to be followed during the construction of the tunnel. These details 

shall include:-mix design, constituents and testing procedures, pumping rates 

and pressures, means of gauging pressures at the point of injection, proof 

drilling pattern to be adopted. 

General 

a) The Contractor shall design a non-shrink Thixotropic Gel 2 part chemical 

grout system for Cavity Grouting. 

b) “Primary Grouting” refers to the initial cavity grouting which takes place during 

shield shove using a pressure grout system. 

c) During the first 100m of the tunnel drive, the Contractor shall demonstrate (by 

proof drilling) the effectiveness of the primary grouting system. 

d) A leachability test on the set grout shall be performed by the Contractor within 

6 months of Contract Award in order to gain approval from the Environmental 

Agency for its use. 

Grout Delivery 

The entire grouting system shall be designed to constantly deliver 1 cum/min 

throughout the complete ring grouting cycle. 

Primary Grout Injection 


Page 29 of 38



PT239.5 

PT239.6 

PT239.7 

PT240 

PT240.1 

a) Primary grout shall be injected by positive displacement. Consideration shall 

be given to providing a ring main system with the incorporation of approved 

retarders and accelerators to control the setting of the grout. The grout pump 

system shall incorporate a safety pressure by-pass arrangement, with means 

of reading the grout pressure at the point of injection. 

b) Primary Grouting shall commence in a manner such the cavity is completely 

filled with grout and all excess air and water is displaced and the grout is 

retained under pressure until the first set takes place. 

Records 

Records at each stage of the grouting process shall be kept, to include quantity 

and pressure applied at each injection point. These records shall be submitted to 

the Project Manager daily. 

Grout Performance 

The minimum compressive strength requirement of all grouts as measured from 

testing cubes shall be:-1.5N/mm² at 24 hours and have an initial set within 10 

seconds with Marsh Flows between 45 and 60 seconds at a base temperature of 

20°C. 

Testing 

Three sample cubes of the grout shall be taken daily to an approved testing 

facility to verify the minimum strength requirement. The results of these tests shall 

be forwarded to the Project Manager. 

Tests shown in Table below to be carried out on the grout. 

item Specification Test method 

Frequency 

On 

ground 

Bleeding Less 

3%(1hour) 

Bleeding test Every 

day 

Consistency 8 to 11 sec Flow test Every 

day 

Gel time 5 to 12 sec Mix test Every 

day 

1 hour Compressive Every 

test with 4cm month 

24 hour 1.5 N/mm 2 cube sample Every 

day 

7 day Every 

month 

28 day 

Every 

month 

In 

each 

tunnel 

Every 

week 

Every 

week 

Every 

week 

Every 

month 

Every 

week 

Every 

month 

Every 

month 

INSTALLATION, MONITORING AND CONTROL FOR SEGMENTAL LINING 

Installation of Tunnel Lining 

Remark 

Solution 

-A 

Solution 

-A 

A+B 

Referen 

ce only 

Referen 

ce only 

Referen 

ce only 

a) Construct rings to correct line and level, in true circular form to preserve the 

circularity of the tunnel. 

b) Select combinations of tapered segment rings to provide specific tunnel 

geometry, and for making corrections as necessary during construction. 

c) Inspect concrete segments and gaskets before transport into the tunnel nd 

the building of the segments in the tailskin. No damaged segments are to be 

taken in to the tunnel and prior to build. 


Page 30 of 38



PT240.2 

PT241 

PT241.1 

PT241.2 

PT241.3 

PT241.4 

PT241.5 

PT241.6 

PT241.7 

d) The Contractor shall tighten bolts across the joints to ensure gasket 

compression in accordance with gasket manufacturer recommendations. 

e) Do not add packings or materials to circumferential joints to adjust line and 

grade unless accepted by the Project Manager. 

f) Stagger radial joints in adjacent rings. Rings may be rotated one or two 

equidistant bolt locations to meet line and grade and curve requirements, 

provided that only T joints result between adjacent rings. 

g) Hangers for utility lines necessary for construction of the tunnel may be 

connected to concrete segments with the Project Manager’s acceptance. 

Monitoring of Segments 

a) The Contractor shall take measurements of the horizontal and vertical 

diameters for each tunnel ring following installation within the tail skin. 

Measurements shall be forwarded to the Project Manager on a daily basis. 

b) Installation tolerances to be as per BTS specification. 

c) The deviation from the true inside diameter of the completed ring shall not 

exceed ± 15mm. 

SURFACE DISPLACEMENT MONITORING 

Preliminary assessments have been made of the settlement resulting from the 

construction of the Works and are shown on drawings 6LYG-A1-02131 to 6LYG- 

A1-02141. These are provided for information only, with no warranty given by the 

Employer. to its accuracy or completeness, and the Contractor shall provide his 

own assessment of the settlement as required under Section 4 Schedule 2 of the 

Works Information. 

The Contractor shall carry out a detailed settlement assessment based on the 

proposed methods of working, proposed alignment, ground conditions and 

ground support details and submit detailed supporting calculations and a full set 

of revised settlement contour drawings for the Project Manager’s acceptance. 

The Contractor shall monitor the effects of tunnel construction, ground treatment 

or dewatering at the surface, including all ground movements and the effects on 

all structures, including the Works. For the purposes of this clause structures 

include buildings at Abbey Mills Pumping Station and Beckton STW, utility 

services including the Northern Outfall Sewer(See Clause PT242.a), railway 

tracks, bridges, railway furniture and all other structures identified as at risk of 

settlement damage by the construction of the Works. 

The Contractor shall submit to the Project Manager, within 60 days of award of 

Contract, a Method Statement detailing his proposal for the monitoring and 

control of surface displacement in accordance with the contract. The Contractor 

shall incorporate, where applicable, the requirements in the clauses below for 

agreement by the Project Manager and interested third parties where appropriate. 

The Employer shall serve notice where required by statute and provide letters 

detailing the Works to third parties which may be affected by the construction but 

do not require formal issue of Statutory notices. 

Monitoring shall be referenced to stable survey stations located outside the zone 

of influence of the works and not subject to ground movement. Such benchmarks 

and co-ordinated stations shall be established and agreed with the Project 

Manager before any ground is excavated and before any ground treatment or 

dewatering takes place. They shall be checked at intervals during the duration of 

the works. 

Surface displacement monitoring for the construction of the bored tunnel shall be 

carried out to ensure that the maximum allowable surface (vertical) settlement is 


Page 31 of 38



PT241.8 

PT241.9 

limited to 5mm at the nearest Structure or identified Utility at Risk 

PT241.10 Settlement monitoring points are to be established for the lengths of the tunnel. 

Settlements monitoring reference arrays comprising three reference points, 

centred on, and perpendicular to the tunnel line, are to be placed at 50m 

maximum centres along the route of the tunnel. The transverse arrangement 

should be matched to the predicted settlement trough. Monitoring is to be 

undertaken to ensure the stability of readings prior to and after tunnelling has 

been completed, and at intervals to identify any trends in readings that 

demonstrate that ground movements are in accordance with predictions and 

control of the stability of works. Monitoring shall be in the form of precise levelling 

unless otherwise instructed by the Project Manager. Monitoring points shall be 

established at least 200m in advance of the face and at least 3 No. 

measurements undertaken to establish base readings. When the face has 

passed the array readings shall be undertaken on a daily basis for 7 days. 

Thereafter readings shall continue on a weekly basis for 4 weeks or until ground 

movements have ceased or as directed by the Project Manager. 

PT241.11 Settlement monitoring reference points shall comprise 50mm long masonry nails 

in road pavements cast in protective concrete, or 10mm diameter 50mm long 

stainless steel round head bolts with stainless steel washers with steel tamp in 

anchors with lead sleeves in structures (Ref. to BRE Digest 386 Monitoring 

building and ground movement by precise levelling). Settlement monitoring 

reference points in verges and other non paved areas shall comprise >1.0m long 

20mm diameter deformed steel bar driven into the ground encased in protective 

concrete. If these systems are not acceptable to the owners of the land, other 

systems are to be proposed by the Contractor for agreement by the Project 

Manager and the relevant third parties. 

PT241.12 

PT241.13 

Monitoring measurements are to be undertaken to an accuracy of +/-0.5mm. 

All monitoring systems shall be removed at the end of the monitoring requirement 

subject to the agreement of the Project Manager and relevant third party or their 

agent. 

PT241.14 Monitoring of settlement of the Network Rail running rails and other infrastructure 

will be carried out by a surveyor approved by Network Rail. The arrangement of 

the installation of the targets on the tracks and ancillary structures is being 

agreed with Network Rail by the Employer as will the frequency of monitoring and 

reporting. The Contractor shall appoint a Network Rail approved surveyor to 

prepare a detailed method statement for the survey work to be approved by 

Network Rail. 

PT241.15 Monitoring of settlement of the LUL running rails and other infrastructure is 

expected to be carried out by LUL’s in-house surveyors. If the Contractor is 

subsequently required to carry out this work he shall employ a surveyor approved 

by LUL under LUL entry procedures. The arrangement of the installation of the 

targets on the tracks and ancillary structures shall be agreed with LUL as will the 

frequency of monitoring and reporting. The agreed monitoring works will not form 

part of the Price and cost relating to this will be dealt with as a Compensation 

Event. 


Page 32 of 38



PT241.16 

The Contractor shall observe, record and analyse the readings to establish trends 

in movement and shall provide a copy of all recorded results to the Project 

Manager. He shall make available results to the Project Manager in accordance 

with an agreed programme. 

PT241.17 Trigger values and actions shall be established for all the monitoring locations 

including settlement arrays, buildings, rail tracks, bridges, railway furniture, 

structures and services monitoring systems. These shall be based on the criteria 

given in the table below or as otherwise specified in Monitoring Plans for 

individual structures and agreed with the Project Manager and Third Parties 

before work commences: 

Trigger Level 

Condition / Limiting 

Value 

GREEN Movement < 

75% of 

predicted 

AMBER 

Movement 

75% to 100% 

of predicted 

Rate of 

Change 

Increasing, 

Constant or 

Reducing 

Increasing, 

Constant or 

Reducing 

Reading 

Frequency 

Defined in 

18.1.6 

(typically 24 

hrs) 

Each shift or 

a min. of one 

per 12 hours 

Action / Reporting 

Monitoring Report to be 

provided to Project 

Manager within 24 hrs 

Monitoring Report to be 

provided to Project 

Manager within 6 hours. 

Contractor to review 

construction operations 

and take action to 

reduce ground losses if 

required. 

RED Movement > 

100% of 

predicted 

Increasing, 

Constant or 

Reducing 

Twice per 

shift or a min. 

of one per 3 

hours 

Prepare to implement 

contingency plan for 

additional measures to 

control ground 

movement as agreed 

with the Project 

Manager. Contingency 

plan to be submitted to 

the Project Manager for 

acceptance within 12 

hours. 

Stop work, secure face 

and immediately inform 


Implement contingency 

plan and additional 

measures to control 

ground movement as 

agreed with the Project 

Manager. 

Tunnelling works may 

only recommence with 

the acceptance of the 


PT241.18 Monitoring of reference arrays is to be undertaken to ensure the stability of 

readings prior to and after tunnelling has been completed, and at intervals to 


Page 33 of 38



identify any trends in readings that demonstrate that ground movements are in 

accordance with predictions and control of the stability of Works. 

PT241.19 The Contractor shall observe, record and analyse the readings in a monitoring 

report to establish trends in movement and shall provide a copy of all recorded 

results to the Project Manager. He shall make available results to the Project 

Manager in accordance with an agreed programme. 

PT241.20 The format of reporting of monitoring results is to be agreed with the Project 

Manager prior to commencing construction activities. Typically it is to contain: 

a) Graphical representation of settlement of buildings/ground over time and 

annotated with tunnel / excavation progress. 

b) Excavation data including material excavated. 

c) Settlement and excavation data trends. 

PT241.21 Hard copy results of the settlement arrays or monitoring points are to be made 

available to the Project Manager on a daily basis when the tunnel face is within 

25m of the array and weekly thereafter in excel and pdf format. 

PT241.22 Monitoring of settlement, scheduled defects and defects arising during the 

course of the Works shall continue at agreed intervals for a period at least until 

the end of the defects date or other such time as agreed by the Project Manager. 

PT242 

PT242.1 

PT242.2 

PT243 

PT243.1 

PT243.2 

PT244 

PT244.1 

DEFECT AND CONDITION SURVEYS 

Pre and post construction defect surveys shall be carried out to a programme and 

methodology as submitted to and agreed with the Project Manager for all 

structures and key utilities identified as being within the 5mm settlement contour 

as shown on drawings 6LYG-A1-02131 to 02141. 

The Northern Outfall Sewer (NOS) 

The Lee Tunnel alignment follows the route of the existing Northern Outfall Sewer 

(NOS) for approx 4.5kms. The Contractor shall carry out a visual Condition 

survey of the sewer as soon as practical after the award of Contract. Record 

drawings of the sewer are included in the Contract for information (Section 6). 

The survey shall be organised by the Project Manager in liaison with the Thames 

Water Operations Division who will provide all safety cover and review Method 

Statements for the survey as required by the Thames Water procedures for Entry 

into Confined Spaces and Live Sewers. The Contractor shall provide a Northern 

Outfall Sewer Condition Survey Report which shall be submitted to the Project 

Manager who, in liaison with the Contractor, will agree any protective measures 

to the NOS that will have to be carried out. 

TEMPORARY ELECTRICITY SUPPLY FOR TUNNEL CONSTRUCTION 

The Employer has agreed to make available a supply of electricity to the 

Contractor for the Construction of the Works. Details of the proposed supply are 

described in Schedule 3 Clause 4 of the Works Information. The Contractor shall 

confirm that the supply will be in accordance with his specific requirements. If the 

supply is insufficient the Contractor shall make his own arrangements for the 

provision of alternative additional power requirements. 

Emergency Generator: Supply an emergency standby generator of such capacity 

and configuration as to automatically and instantly come on line in the event of a 

power failure, without interruption, and to operate ventilation, lighting, pumping, 

communications and other critical systems. 

TREATMENT OF ARISINGS 

Spoil Processing requirements for Slurry TBM 


Page 34 of 38



a) The Contractor is responsible for the design of the slurry separation plant, 

and shall comply with the MINIMUM requirements as set out below. The 

Contractor shall take account in the design of his plant the materials to be 

excavated in the Graben structure as defined in the Geotechnical Baseline 

Report (GBR). Details of the design shall be submitted to the Project 

Manager for acceptance within 28 days of contract award. 

b) The Separation Plant shall have the capacity of processing 300 cu.m. of solid 

excavation material per hour. The centrifuges shall have the capacity for 

processing 200 cu.m. per hour of chalk fines and the removal of all particles 

above 5 microns in size. 

c) The moisture content of the slurry paste for disposal shall not exceed 45% 

unless agreed otherwise with the Project Manager. 

PT244.2 

PT244.3 

PT244.4 

PT244.5 

PT244.6 

PT244.7 

Spoil Processing requirements for EPB 

a) The moisture content of the material for disposal shall not exceed 45% unless 

agreed otherwise with the Project Manager 

Wastewater can be disposed of as follows: 

a) The wastewater from the slurry separation plant can be discharged into the 

chamber, adjacent to the Work Site, as shown on Drg 6LYG-A1-02208A from 

which it will discharge to the to the Head of the works in Beckton STW. The 

Contractor shall be responsible for maintaining the discharge pipe in good 

working order. The wastewater shall not exceed the following criteria, and 

testing samples shall be submitted weekly to the Project Manager, for 

analysis by Thames Waters’ Operations team:- 

i) Suspended Solids - 750 mg/l 

ii) COD - 375 mg/l 

iii) Ammonia - 25 mg/l 

iv) Sulphate - 1400 mg/l 

b) For water not meeting the criteria in (a) above, the water will be disposed of 

offsite, in agreement with the Project Manager. 

The Contractor shall allow for processed spoil for disposal to be delivered by 

conveyor to the start of the jetty bridge as shown on Drg 6LGY-A1-02208. The 

conveyor shall be capable of transporting a minimum of 400 cu.m.of spoil per 

hour. The location for barge loading is identified on Drg 6LGY-A1-02208. The 

Contractor shall manage the logistics of river transportation of other materials to 

be delivered to the jetty bridge. (refer to ITT). 

The Separation Plant shall be new and purchased for the Project. 

The Contractor shall, using similar materials to those identified in the GBR for the 

tunnel alignment, conduct trials to demonstrate to the satisfaction of the Project 

Manager prior to purchasing the separation plant that it can meet the 

requirements above. 

Storage of Excavated Material, both EPBM and SPBM 

2 no. existing sludge tanks (approximately 4000m3 storage volume each) as 

shown on Drg 6LYG-A1-02208A can be made available to the contractor for 

storage of excavated material, if required by the Contractor. These tanks 

currently store sludge and the initial emptying and cleaning of these tanks shall 

be under a Provisional Sum 


Page 35 of 38



PT245 

PT246 

PT246.1 

PT246.2 

PT246.3 

PT246.4 

PT247 

PT247.1 

PT247.2 

TBM LAUNCH FROM OVERFLOW SHAFT 

The TBM will be launched from the 25m ID Overflow Shaft at Beckton STW. 

From the Site Information and GBR, the launch of the TBM will be within the 

Greenwich Fault Zone of the chalk, the Employer views this as one of the highest 

risks to the success of this Project and the Contractor shall, within 28 days of the 

award of Contract, submit to the Project Manager a detailed Method Statement of 

his Means and Methods for the launch of the TBM, including ground treatment 

and temporary works proposals. A Risk Assessment shall also be provided. 

CONSTRUCTION TOLERANCES 

Bored Tunnel Tolerances 

a) Tunnel shall be constructed to the alignment as defined in the Works 

Information. 

b) Maximum tolerances allowed in respect of the departure of any point on the 

bored tunnel alignment from its designed centreline shall not exceed 50mm 

horizontally and 50mm vertically. 

d) No ponding anywhere in the tunnel shall be deeper than 25mm. 

e) The maximum and minimum measured diameter in any one ring shall be 

within 0.5% of the theoretical design diameter of the ring. 

f) The maximum lipping between the edges of the adjacent segments shall not 

exceed 5mm. 

Inner Lining Tolerances 

a) At no point shall the lining thickness be less than that recommended by the 

designer. 

b) As stated in PT246.1 the maximum departure of any point on the inner lining 

shall not exceed 50mm from its designed position. 

c) No ponding anywhere in the tunnel shall be deeper than 25mm 

d) The internal diameter of the inner lining measured at any point around the 

circumference shall depart no more than 10mm from the designed diameter. 

e) If cast in sections there shall be no lipping between the panel joints. 

Groundwater Ingress Primary Lining 

a) The infiltration volume of water for the total length of tunnel shall not exceed 

0.1 litre per hour per linear metre of nominal bore. 

b) Sealing of leaks in the segmental lined tunnel shall be carried out prior to the 

secondary lining installation 

Groundwater Ingress Inner Lining 

There shall be no visible damp patches or running water present on the finished 

surface of the lining. 

AS-BUILT TUNNEL SURVEY 

On completion of the tunnel construction the Contractor shall carry out an As-Built 

Tunnel Survey in the bored tunnel. The accuracy of the survey shall be to ±20mm 

for vertical and horizontal alignment. 

The As-Built Tunnel Survey shall be completed as soon as practical following the 

completion of the tunnel, the As- Built Survey data is to be finalized and 

submitted to the Project Manager prior to the final acceptance of the tunnel. 


Page 36 of 38



PT248 

PT248.1 

PT248.2 

PT248.3 

PT248.4 

SECONDARY LINING DESIGN AND INSTALLATION 

The Contractor shall be responsible for the design and installation of a Reinforced 

Concrete Inner Lining in accordance with the Works Information. The design must 

allow for the build tolerances in the primary lining. 

The design life of the Inner Lining shall be 120 years. 

The Specification for the design and construction will be the British Tunnel 

Society Specification for Tunnelling and the References as detailed in PT402 

Special Clauses are detailed in this Section 

The Contractor shall submit to the Project Manager for his acceptance in 

accordance the timescales of Schedule 4 and the requirements of Schedule 6 of 

the Works Information. This includes, but is not limited to, design calculations and 

drawings of the proposed Reinforced Concrete Inner Lining. The design 

submissions shall include as a minimum details of design standards used, 

loading conditions, design assumptions, design parameters, method of analysis, 

references and proposals as to how they will meet the water ingress specification 

PT246.4 and detailed drawings and installation methodology. 

PT248.5 The Contractor shall submit to the Project Manager for his approval within 90 

days of award of Contract a detailed Method Statement of the proposed 

methodology for the construction of the Inner Lining. This is to include but not 

limited to details of the location of the Concrete Production, transportation of the 

concrete to the location of the placement, detailed drawings of the proposed 

arrangement of the internal formwork, method and timing of the fixing of 

reinforcement if proposed. 

PT248.6 

PT248.7 

PT248.8 

PT248.9 

PT248.10 

PT248.11 

The Contractor can work from Beckton and/or Abbey Mills on the installing of the 

Inner Lining should he so decide as part of the Construction methodology. 

Account should be taken of any restrictions imposed by the Planning Agreements 

at either site as described in the Works Information. 

Concrete Mixes shall be designed and mixed in accordance with the 

requirements of PT400. 

Concrete mixes shall be designed to minimise cracking of the lining and to ensure 

that crack widths do not exceed the permitted width specified in Eurocode 2-part 

3:2006 and the National Application Document 

Concrete shall be compacted by high frequency mechanical vibrators. type shall 

be used, supplemented in the case of steel formwork by heavy duty formwork 

vibrators where necessary. Vibrators shall not be used to distribute concrete from 

the point on placing 

The Contractor shall submit to the Project Manager for acceptance within 90 days 

of the award of Contract a concrete placement Method Statement. This shall 

include the proposed construction joint detail and locations. This shall also 

include proposals for the testing of the inner lining concrete to ensure that the 

minimum concrete strength, as specified in the Contractor’s design submission, 

has been achieved prior to removal of the formwork, and any testing procedures 

the Contractor proposes to carry out to ensure that there are no voids in the 

concrete inner lining. The submission shall include a detailed methodology to 

eliminate air entrapment and voids between the inner lining and the primary lining 

when placing the concrete and pressure grouting procedures and his proposed 

method for ensuring the completed lining is free from voids 

Where encountered the Contractor shall grout any cavities and voids between the 

inner lining and the primary lining. Grouting will not be allowed until the concrete 

has been demonstrated as achieving the designed 28 day strength. Temporary 

grout pipes can be provided in the crown of the lining and used for the elimination 

of air entrapment and voids, these shall not remain within 40mm of the surface of 

the finished concrete. 


Page 37 of 38



PT248.12 

Design Loadings 

a) The internal lining shall be designed to resist the full internal hydrostatic 

pressure imposed when the tunnel and shaft systems fill to shaft roof soffit 

level. 

b) The internal lining shall be designed to resist the full external hydrostatic 

pressure imposed from the groundwater level as defined in the GBR. 

The loadings defined in a) and b) above shall be applied both simultaneously and 

separately. 


Page 38 of 38




PT300 CONSTRUCTION OF THE 3.05m DIAMETER STATION “A” CONNECTOR 

TUNNEL AT ABBEY MILLS : SPECIFICATION FOR THE TUNNEL BORING MACHINE 

AND TUNNEL CONSTRUCTION.......................................................................................... 2 

PT301 SUMMARY........................................................................................................... 2 


PT303 DEFINITIONS ...................................................................................................... 2 

PT304 SUBMITTALS ...................................................................................................... 3 

PT305 GENERAL – TUNNEL BORING MACHINE ........................................................ 3 

PT306 MINIMUM REQUIREMENTS FOR TBM TUNNELLING EQUIPMENT............... 4 

PT307 CUTTERS ............................................................................................................ 4 

PT308 CUTTER HEAD ................................................................................................... 4 

PT309 EXCAVATED MATERIAL MUCKING SYSTEM .................................................. 5 

PT310 SEALS.................................................................................................................. 6 

PT311 GROUTING.......................................................................................................... 6 

PT312 SEGMENT ERECTOR......................................................................................... 6 

PT313 TBM/SEGMENTAL LINING INTERFACE............................................................ 6 

PT314 CONTROL AND INTERLOCKS........................................................................... 7 

PT315 GUIDANCE SYSTEM .......................................................................................... 7 

PT316 APPLICABLE CODES AND REGULATIONS...................................................... 8 

PT317 TAIL SEAL GREASE INJECTION ....................................................................... 8 

PT318 OTHER FEATURES ............................................................................................ 8 

PT319 FIRE PREVENTION – TBM AND BACKUP ........................................................ 8 

PT320 TBM FACTORY TESTING................................................................................... 9 

PT321 QUALITY ASSURANCE ...................................................................................... 9 

PT322 TUNNEL HEALTH AND SAFETY ASSURANCE ................................................ 9 

PT323 TUNNELLING CONSTRUCTION ...................................................................... 11 

PT324 GENERAL TUNNELLING CONSTRUCTION REQUIREMENTS...................... 11 

PT325 GROUTING........................................................................................................ 12 

PT326 INSTALLION, MONITORING AND CONTROL FOR SEGMENTAL LINING .... 13 

PT327 SURFACE DISPLACEMENT MONITORING .................................................... 14 

PT328 BUILDING DISPLACEMENT MONITORING .................................................... 14 

PT329 TEMPORARY ELECTRICAL SUPPLY FOR TUNNEL CONSTRUCTION ....... 15 

PT330 CONSTRUCTION TOLERANCES .................................................................... 15 


Page 1 of 15



PT300 

PT301 

PT301.1 

PT301.2 

PT301.3 

PT302 

PT303 

PT303.1 

PT303.2 

PT303.3 

PT303.4 

PT303.5 

CONSTRUCTION OF THE 3.05m DIAMETER CONNECTOR TUNNEL AT 

ABBEY MILLS : SPECIFICATION FOR THE TUNNEL BORING MACHINE AND 

TUNNEL CONSTRUCTION 

SUMMARY 

The work of this Section includes, but is not limited to, providing all labour, 

materials, tools, equipment, and incidentals necessary for a tunnel boring 

machine and tunnel construction, in accordance with the Contract Documents. 


a) Tunnel Boring Machine includes, but is not limited to: design, manufacture, 

furnish, maintain and testing of a tunnel boring machine for the express 

purpose of constructing TBM excavated tunnels. 

b) Boring Tunnel includes, but is not limited to: mining of tunnels, installation of 

precast segment tunnel lining, temporary tunnel facilities, geotechnical 

monitoring, control of ground loss, settlement and heave, and removal and 

disposal of excavated material. 

c) As-Built Tunnel Survey 

This is a performance specification. The Contractor shall be responsible for the 

selection and complete design of the tunnel boring machine and tunnel 

construction systems. The Contract Documents provide parameters and design 

criteria for this portion of the Work. 


See PT204 in “Specification for New Tunnel Boring Machine and Tunnel 

Construction”. 

DEFINITIONS 

TBM excavation: The construction of underground tunnels by mechanical means 

using a tunnel boring machine. 

Segmental tunnel lining: Precast concrete segments that are bolted together 

inside the TBM tail shield to form a gasketed, watertight tunnel lining ring. The 

lining shall be designed to withstand both handling loads and all ground and 

water loads. Refer to PT400 for the detailed Specification requirements the 

design and supply of the Tunnel Linings. 

TBM: As used in this Section, the term TBM means the total system of the tunnel 

boring machine including trailing gear and appurtenant support equipment, 

materials and any items of plant which are necessary for the sustaining of TBM 

excavation operations all to be designed in accordance with the requirements of 

this Section. The TBM shall have the ability to apply a sustained and controlled 

pressure on the tunnel face within a pressure bulkhead located behind the face 

to form a plenum under pressure with the remainder of the tunnel maintained at 

atmospheric pressure. 

EPBM: An Earth Pressure Balanced TBM with a pressure bulkhead located 

behind the face to form a plenum under pressure. Conditioners can be injected 

into the plenum to control the quality of the excavated material through a screw 

conveyor in closed mode and belt conveyor in open mode. 

SPBM: A Slurry Pressure Balanced TBM utilizing a controlled dense slurry in a 

pressure chamber in the head of the machine to stabilize the face and minimize 

settlement. The resultant slurry, with excavated material, is removed to the Slurry 

Separation plant by pumping. 


Page 2 of 15



PT304 

PT304.1 

PT304.2 

PT304.3 

PT305 

PT305.1 

PT305.2 

PT305.3 

PT305.4 

PT305.5 

PT305.6 

PT305.7 

SUBMITTALS 

To be submitted within 21 days from award of Contract. All submittals will be 

reviewed and returned within 14 days of Engineer’s receipt. 

See PT204 in “Specification for new Tunnel Boring Machine and Tunnel 

Construction” 

The Contractor shall state whether the tunnelling equipment proposed is to be 

new or refurbished. If refurbished elements are proposed the Contractor shall 

provide a detailed history of the use of the major components with the original 

calculated design life of the element together with supporting calculations, 

specifications and design. These components shall include but are not limited 

to: 

• Main Bearing 

• Muck excavation and handling systems (including slurry treatment facility if 

applicable). 

• Guidance system. 

• Segment transport and erector systems. 

• Tail seals and primary grouting system. 

• Gas detection system. 

• Services including ventilation, water management systems, utilities support 

and fire suppression systems. 

The following submittal is to be made a minimum of 90 days before the 

programmed date of TBM Start-Up: 

a) Tunnel Specific Safety Statement. 

GENERAL – TUNNEL BORING MACHINE 


furnishing a tunnel boring machine (TBM), as defined in this Section, for the 

express purpose of constructing a 3.05m ID TBM in materials of soil types, 

densities, gradations (PSD), strength, abrasivity and hydrostatic pressures 

described in the GBR and Contract Documents. 

The TBM shall be capable of applying a sustained and controlled pressure on 

the tunnel face to comply with the surface settlement limitations as required by 

this Specification. 

The bored tunnel lining shall be bolted precast concrete segments, with an 

EPDM gasket as specified in PT500 

The selection of tunnel boring equipment and construction methods shall be 

compatible with the ultimate use of the tunnels, the ground and groundwater 

conditions, the depths of tunnels and the proximity of existing structures and 

services. 

Design TBM and backup equipment to negotiate the curves in the alignment and 

meet the specified alignment tolerances. 

Diameter of finished tunnel: to be a minimum of 3.05m ID to match the 

Contractor’s design and to produce minimal over-excavation and least necessary 

clearance. 

Equip TBM with integrated safety systems in accordance with applicable 

regulatory requirements for underground construction equipment and in 

accordance with BS6164 2001 “Safety in Tunnelling in the Construction 

Industry”. 


Page 3 of 15



PT305.8 

PT306 

PT306.1 

PT306.2 

PT307 

PT307.1 

PT307.2 

PT307.3 

PT308 

PT308.1 

PT308.2 

PT308.3 

All soil conditioning materials, oils, greases, sealing compounds and any other 

material injected into or in contact with the soil, rock or ground water which is 

used during the mining operation shall be compliant with all relevant regulatory 

agencies and the requirements of the Contract. 

MINIMUM REQUIREMENTS FOR TBM TUNNELLING EQUIPMENT 

With particular reference to this Contract Document, the requirements as 

detailed in this Section will not modify or detract in any way whatsoever from the 

Contractor’s sole responsibility for the selection, design and operation of the 

tunnelling plant and equipment. 

The Contractor shall assemble, maintain, operate and remove all tunnelling 

equipment necessary to construct and complete the tunnel in accordance with 

the Contract Documents and the ground conditions encountered. The Contractor 

shall also ensure that the design, manufacture and operation of the tunnel mining 

equipment, including the TBM, are carried out in such a manner that the tunnel 

can be constructed and completed in accordance with the time of completion 

requirements of the Contract. 

CUTTERS 

Cutter design shall take into account the abrasivity of the ground conditions. The 

cutters shall be hard faced to a design giving best wear resistance. Cutters shall 

be backloaded such that access for repair and replacement can be carried out in 

safe working conditions. 

The Contractor shall pay particular attention to protection of the moving (rotating) 

elements of the machine against the potentially abrasive nature of the ground. 

The TBM shall be equipped with Chromium Carbide abrasion resistant plating or 

other approved hard facing to all exposed moving surfaces of the TBM, for 

example cutting head and screw conveyor. 

Design components for maximum abrasion resistance and durability. Minimize 

disc cutter wear to the greatest extent possible when not currently in use to 

perform tunnel excavation by such means as designing hubs and bearings to 

allow discs to be readily rotated by hand, and by limiting disc cutter projection 

beyond the cutter head face. 

CUTTER HEAD 

The TBM shall incorporate a soil conditioning system for injection directly onto 

the face. The screw conveyor (if EPBM closed mode) shall also incorporate a 

facility for soil conditioning. Soil conditioning agents shall be bio-degradable and 

acceptable for the excavated materials to be used as a fill. All ports shall be 

independent. 

The TBM shall be capable of excavating through the ground conditions indicated 

in the Contract Documents and geological and geotechnical information available 

to the Contractor without interruption of the excavation operations 

Provide capacity to start cutter head with not less than 1.25 times rated full load 

torque. Provide clutches or hydraulic assist for a variable frequency electric drive 

(VFD) or use a variable speed hydraulic drive system. Thrust System and 

Steering 

a) Design TBM to provide forward propulsion by thrust cylinders that react 

against the installed segmental liner without damaging the liner. 

b) Equip the thrust cylinders with shoes or pads to distribute the jacking forces 

to the liner without damaging the liner. Design the thrust cylinder shoes to 

be consistent with segment and segment joint design while capable of 

individual and synchronized thrust cylinder actuation while limiting the 


Page 4 of 15



PT308.4 

PT308.5 

PT309 

PT309.1 

PT309.2 

PT309.3 

PT309.4 

PT309.5 

PT309.6 

PT309.7 

maximum force that each thrust cylinder may exert so that liners are not 

damaged. Thrust cylinders shall resist displacements when idle. 

c) The TBM shall have a proven anti-roll system. 

The shield shall be articulated, subject to the following: 

a) Design and locate an articulation joint (or joints) as required, to assist 

constructing the tunnel to the theoretical alignment indicated in the Contract 

Documents and within the specified tunnel construction tolerances. 

b) Equip the articulation joint with a seal replaceable from within the TBM to 

prevent the entry of slurry, grout, fines or other foreign material. Provide a 

means for cleaning the articulation joint from inside the TBM to maintain its 

full range of articulation. 

Drive System 

a) Provide a TBM having sufficient drive motor power so the machine is not 

torque limited while operating in open earth pressure balance mode or slurry 

mode for any ground materials or conditions described in the Contract 

Documents. 

b) TBM drive system shall be bi-directional. 

EXCAVATED MATERIAL MUCKING SYSTEM 

If proposing an EPBM, fit and operate earth pressure balance tunnel boring 

machine with a screw conveyor in closed mode and a conveyor belt in open 

mode to remove excavated material from the cutter head chamber. Design the 

screw conveyor for operation in abrasive soil and for efficient replacement from 

within the tunnel. 

If proposing an EPBM, the screw conveyor shall be designed to maintain the 

required face pressure within the cutterhead chamber and the entrance to the 

screw conveyor. Pressure shall be reduced to atmospheric at the screw exit by 

control of the screw conveyor. The tunnel boring machine shall be capable of 

controlling face pressure to within ± 0.3Bar of the desired pressure. 

If proposing an EPBM, design the screw conveyor to be capable of being closed 

and sealed against earth pressure at each end. The front of screw conveyor shall 

be located at the base of the pressure chamber and shall project into chamber 

when operating. The screw shall be capable of being withdrawn in order to close 

front bulkhead door for maintenance and removal of obstructions. 

Fix the exit/outlet end of the EPBM screw conveyor with a pressure lock-out 

device to separate the pressurized ground water and muck from atmospheric 

pressure. 

Provide and Calibrate, as a minimum, two TBM pressure cells in the mucking 

chamber and a minimum of two pressure cells on the screw conveyor all as 

recommended by manufacturer or as needed to assure accuracy of pressure 

measurements. 

Use a conveyor, rail or slurry system for muck transport in the tunnel. Design the 

system selected for materials with abrasive fines and high water content. All 

proposed systems shall take into consideration the designed gradients of the 

tunnel and the safety of the underground personnel. 

For all conveyor belt systems, there shall be an audible alarm with a red flashing 

warning light giving the operatives advanced warning that the conveyor belt is 

about to start moving. Emergency stop buttons shall be provided at all working 

points and at frequent intervals along the conveyor belt. Restarting of the 

conveyor shall only be possible from a single position and under the control of a 

single person. 


Page 5 of 15



PT309.8 

PT309.9 

PT310 

PT310.1 

PT310.2 

PT310.3 

PT311 

PT311.1 

PT311.2 

PT312 

PT312.1 

PT312.2 

PT312.3 

PT313 

PT313.1 

For SPBM, the TBM shall be designed to work under all conditions described in 

the Contract Documents. This includes the complete slurry system required to 

stabilize the face and drive the tunnel. The slurry machine shall be capable of 

controlling the applied face pressure to within 0.3Bar of the hydrostatic head. 

For SPBM, the design of the slurry treatment plant shall accommodate the types 

and quantities of geological materials anticipated and to remove solids from the 

suspension at a sufficiently fast rate so that the slurry treatment does not limit the 

TBM advance rate. The slurry shall be reconditioned or replaced with fresh slurry 

when the slurry properties are unsatisfactory. 

SEALS 

Provide main bearing seals rated for tunnelling conditions and maximum 

pressure anticipated from the sum of all forces acting on the seals 

simultaneously and all machine operating characteristics related to the main 

bearings. Design the seals for the articulation joint, tail shield and probe ports for 

maximum hydrostatic and earth pressure. 

Shield tail seals shall incorporate a redundant system of wire brushes to seal 

against maximum hydrostatic and cavity grout pressure with due consideration of 

the liner segment design and the influence of liner grouting in seal design. 

Provide a minimum of three seals continuously fed with fibrous grease whenever 

the TBM advances. 

Tail seals other than the rear seal shall be replaceable from within the tunnel 

during a drive. 

GROUTING 

Cavity Grouting: Provide a computer operated grouting system linked to TBM 

systems to calculate grout quantities and continuously adjust grout injection rate 

and pressure on the basis of the TBM advance rate and other data. 

The annulus void between the tunnel lining extrados and the excavated ground 

shall be fully grouted with a grouting system and mix approved by the Project 

Manager 

SEGMENT ERECTOR 

The segment erector shall be compatible with the TBM and liner system to 

ensure safe and efficient segment installation and shall have an appropriate 

factor of safety for the anticipated loads. 

The erector shall be capable of actuation in the axial, radial, and circumferential 

directions and in the three articulation angles corresponding to the six degrees of 

freedom. Design the erector to grip and erect the segments so that they are 

positioned accurately, so that segments are aligned within the required 

tolerances, so that gaskets are fully compressed, and so that no damage or 

distortion of the segments occurs. 

All hand held electrical equipment, such as the pendant controls for the segment 

erector, shall be in a watertight enclosures and the control circuit protected by a 

Ground Fault Interrupter Circuit. 

TBM/SEGMENTAL LINING INTERFACE 





limited to alignment control, handling, erecting, jacking and grouting. 


Page 6 of 15



PT313.2 

PT313.3 

PT313.4 

PT313.5 

PT314 

PT314.1 

PT314.2 

PT314.3 

PT314.4 

PT315 

PT315.1 

PT315.2 

PT315.3 

Maximum ram thrust contact pressure at any point and any time on the liner 

system ram thrust shall not exceed 50% of the segment 28-day compressive 

strength. 

Thrust pads are to be designed such that they shall not damage gaskets or 

segments. 

Equip TBM to allow continuous, complete backfill grouting of the annulus 

between the concrete segments and excavated surface. 

Tail seal grease shall be compatible with the liner system gaskets and materials, 

shall be inert, shall not contaminate the surrounding ground or groundwater and 

shall not in any way cause the long term deterioration of the liner concrete, the 

joint connector, the gaskets, seals or joint packers. 

CONTROL AND INTERLOCKS 

The TBM cutter head shall be prevented from moving at any point during any 

maintenance or entry. An interlock should be provided from the control cabin to 

allow remote inching operation of the cutter head. Contractor to establish safety 

procedures, for approval by the Engineer, which will include, among other 

issues, a procedure to ensure that all personnel have evacuated the cutter head 

and front chamber before any movement is undertaken. This provision is 

intended to assist cutter tool changes with local indexing of the cutter head. The 

cutter head drive shall have fail-safe braking system to prevent inadvertent 

movement. 

All erector load-holding functions shall have a fail safe alarm system. Rotational 

drives shall be fitted with fail safe brakes. 

The segment erector shall be fitted with the selection and audibility of safe lifting 

alarms. 

An interlock shall be provided that prevents extension of the shove rams should 

grout delivery through the tail skin be interrupted or blocked. The Contractor shall 

provide a method of automatic data logging and measuring volume and pressure 

of grout injected per tunnel lining ring. 

GUIDANCE SYSTEM 

The Contractor shall provide a TBM Guidance and Control System with laser 

theodolite. This shall be a commercially manufactured system. 


a) Reference should be made to Contract Documents for required accuracy 

and tolerance and other matters affecting the operation of the system. 

b) The tunnelling system shall be designed to maintain a clear space for the 

guidance system and laser beam, irrespective of shield or TBM orientation. 

c) The data shall be presented on displays at the underground Machine 






b) Intervals between manual checking of data produced by the guidance 

system (lengthened intervals may be adopted as experience is gained) 

c) Intervals at which survey control points are to be established, based upon 



Page 7 of 15



d) The guidance system must be fully operational whenever the TBM is 

advancing. 

PT316 

PT317 

PT318 

PT318.1 

PT318.2 

PT318.3 

PT318.4 

PT318.5 

PT318.6 

PT318.7 

PT318.8 

PT319 

APPLICABLE CODES AND REGULATIONS 

The TBM and its components shall meet all applicable codes and regulations, 

and all requirements posed by the electric power suppliers and any other agency 

that has jurisdiction. 

TAIL SEAL GREASE INJECTION 

Tail Seal grease injections shall be automatic and continuous to ensure effective 

filling between the brushes. Injection of grease shall be in accordance with the 

TBM manufacturer’s written requirements, and shall be a positive distribution 

system to ensure even distribution of grease, details of which shall be made 

available to the Engineer. Tail Seal grease shall be fireproof. 

OTHER FEATURES 

Provide the TBM with probe hole and grouting drilling capability such that the 

probe and grout holes can be maintained a minimum of 20 metres ahead of the 

TBM cutterhead. The probing ports shall be fitted with suitable glands and valves 

to withstand the pressures envisioned. 

Provide method to test for the presence of hazardous or explosive gas in 

accordance with Health and Safety regulations requirements. Particular attention 

should be taken for the potential for migration of contaminated material from the 

Abbey Mills Site details of are given in Schedule 6 of the Works Information and 

the Factual Site Investigation Reports issued as part of the Contract 

All electrical power, control and safety systems shall have a minimum moisture 

ingress protection rating of NEMA 12. All cables in the tunnel shall be LSF (Low 

Smoke and Fume) or LSOH (Low Smoke Zero Halogen) sheathed. If the TBM 

has a high voltage transformer this shall have an over temperature alarm and 

shall include all safety devices as required by the regulatory authorities. 

Provide an environmental monitoring system that detects levels of potentially 

hazardous gases. Systems shall be arranged with adjustable limits and shall 

have a first level warning signal and a second level with automatic shut off of 

tunnelling equipment in accordance with Health and Safety Regulations 

requirements. Gases to be monitored shall include methane, oxygen, hydrogen 

sulphide, carbon dioxide and carbon monoxide and other gases, mists and 

fumes. 

The Contractor shall supply Calibration Test Certificates for gas detection 

system, pressure cells in excavation chamber and screw conveyor, TBM 

guidance system and grout pressure gauges. Certificates to be updated in 

accordance with the manufacturers recommendations. 

In order to provide a clean environment for placing of the invert segment plate, 

the Contractor shall take appropriate measures to keep the shield area free from 

water and spoil material. Pumping facilities in the shield area of the TBM shall be 

designed to allow sufficient space for the equipment proposed. 

The TBM shall be designed to withstand the full overburden pressure and 

anticipated hydrostatic pressures. 

Only TBM synthetic hydraulic oils HFDU (biodegradable, fire resistant, 

polyesters) shall be used. All oils must be approved by the TBM manufacturer. 

FIRE PREVENTION – TBM AND BACKUP 

The TBM shall be provided with the following minimum systems of fire prevention 

but not limited to: 


Page 8 of 15



PT320 

PT320.1 

a) Emergency Plunger buttons at suitable locations to activate a fire alarm. 

b) Hand held extinguishers provided with colour coded covers in suitable 

locations. 

c) A means of rapidly shutting off fresh air ventilation to the tunnel face, after 

the area has been evacuated. 

d) Conveyor belting, rubber covered rollers and other similar parts to be 

manufactured in materials that reduce the fire and toxic fume risk (Health 

and Safety regulations approved). 

e) Fire suppression system –manually operated 

TBM FACTORY TESTING 

The Contractor shall submit, at least 30 days prior to the commencement of any 

factory tests, a test schedule and program for the TBM and back-up system. The 

Contractor shall allow for attendance by the Engineer at the factory tests. 

PT320.2 The TBM shall be tested in accordance with the manufacturers 

recommendations and a certificate of confirmation of compliance with the 

requirements of this Section, together with a copy of the test results, shall be 

signed by the Contractor and the TBM manufacturer and shall be forwarded to 

the Engineer prior to the TBM being delivered to the Worksite. 

PT320.3 

The test shall include a demonstration mock up of the concrete segment erection 

system, using the precast concrete segments as proposed for the project. 

PT321 

PT321.1 

PT321.2 

PT322 

PT322.1 

PT322.2 


TBM Manufacturer: The proposed TBM manufacturer shall be a recognised 

commercial TBM manufacturer with no less than 5 years of successful 

experience in the design and manufacture of TBMs of the type proposed by the 

Contractor. 

For this project the Contractor shall use only qualified and experienced person in 

the following key positions:- Contract Manager, Construction Agent, TBM 

Mechanical Foreman and Electrical Foreman and TBM Operators. The 

Contractor shall submit with his tender return the names and CVs of those key 

persons he proposes to use on this project. 

TUNNEL HEALTH AND SAFETY ASSURANCE 

As part of the Contractor’s Safety program the Contractor shall produce a Tunnel 

Specific Safety Statement detailing the precautions to be implemented to protect 

personnel working in the tunnel from the construction methodology risks 

associated with tunnelling at the designed gradients and long section. These 

shall include: 

a) Risk of runaway trains and derailments 

b) Tunnel inundations 

c) Control of water and standby provisions 

d) Temporary Tunnel Ventilation System 

e) Emergency evacuation of tunnel 

f) Fire precautions. 

g) Management of rail and pedestrian movements in the tunnel. 

h) Tunnel Interventions for routine maintenance and unplanned events 

Bored Tunnel Temporary Facilities 


Page 9 of 15



PT322.3 

PT322.4 

PT322.5 

PT322.6 

PT322.7 

PT322.8 

a) The Contractor shall design, provide, operate and maintain for duration of 

tunnelling construction a temporary ventilation system, which conforms to 

the Health and Safety requirements. The equipment shall be adequate to 

maintain sufficient supply of fresh air in underground work areas. 

b) The design of the ventilation system shall take into account any mitigation 

measures the Contractor may deem necessary having regard to the 

potential for the migration of any gases and contaminated material into the 

tunnel or shafts from the contaminated materials as detailed in the Reports 

and Site Information at Abbey Mills to be found in Schedule 6 of the Works 

Information 

i) Mechanical ventilation systems shall not be removed without the 

approval of the Project Manager. 

ii) As a minimum, in good air quality, when the excavations are occupied 

by workers, the ventilation system shall be designed to deliver fresh air 

at a volumetric flow rate equal to 20mtrs per minute times the crosssectional 

area of the tunnel. A higher volumetric flow rate shall be 

provided if necessary 

iii) Power to the main ventilation system shall not be interrupted in the 

event of an alarm of the air monitoring system. 

iv) Advance of the ventilation system shall be made a regular part of the 

normal tunnel excavation cycle. 

Temporary Tunnel Lighting System 

The Contractor shall provide a temporary lighting system in the tunnel which 

conforms to the requirements of BS6164:2001“Code of practice for safety in 

tunnelling in the construction industry”. Lighting in the tunnel shall extend the full 

length of the tunnel and not be less than that required for safe working and 

access. An alternative source of power and emergency lighting system shall be 

provided to allow emergency securing operations and safe evacuation in the 

event of a primary power failure. An adequate number of hand lamps shall be 

located at key points underground. 

Temporary Personnel Walkway 

The Contractor shall provide walking access in the tunnel at all times. This shall 

have a firm, level, slip-resistant and continuous surface and shall be suitable for 

use in emergencies. 

Hop ups for pedestrian safety shall be provided in the tunnel at a minimum of 

100mtr centres. 

Temporary Locomotive Track 

The track should be properly supported and secured against displacement in the 

tunnel. The entire length of the track shall be examined not less than once a 

week and the results of this inspection shall be forwarded to the Engineer. 

Defects shall be recorded and remedial action will be promptly implemented 

when identified. 

Temporary Pumping 

Provide intermediate pumping stations and reserve pumping capacity at the any 

point of the tunnel as required to remove groundwater inflows and construction 

water. 

Fire Extinguishers 

Fire extinguishers shall be provided at a minimum every 500 metres of the 

running tunnels. They shall be maintained in accordance with the manufacturer’s 

recommendations. 


Page 10 of 15



PT322.9 

PT322.10 

Smoking Policy 

There shall be no smoking in the tunnel. 

Breathing Sets 

Approved emergency breathing apparatus or approved oxygen self-rescuers as 

appropriate shall be provided and kept with all persons visiting or working in the 

tunnel for the duration of their time in the tunnel. All such equipment shall be 

regularly maintained in accordance with the manufacturers recommendations, 

records shall be kept in the Contractors site office and made available for 

inspection by the Engineer. 

PT323 

TUNNELLING CONSTRUCTION 

PT323.1 The construction of the Connector Tunnel shall be carried out from Shaft F, 

which is the 25m internal diameter Reception shaft for the Lee Tunnel, and shall 

be driven at an upward grade to Shaft A, all as shown on the Contract Drawings. 

Tunnel driving from Shaft A will not be permitted due to the restricted available 

working space at that shaft. The Contractor shall ensure that sufficient float has 

been allowed in his Construction Programme to ensure that any delay in the 

construction of the Station A Connection Tunnel and Shaft F itself should not 

delay the completion of the Works. 

PT323.2 

PT323.3 

PT323.4 

The Contractor shall monitor and analyze lubricants in critical areas of the 

tunnelling equipment on a weekly basis. This shall be performed by an 

independent specialist to identify the presence of any pollutants. Critical areas 

shall include all major sealing systems, main bearing, final drive gear, hydraulic 

systems and motor gear boxes. The results of the analysis shall be forwarded to 

the Engineer upon receipt together with any proposals for remedial action where 

pollutants have been identified. 

The Contractor shall forward to the Engineer details of proposals for the routine 

periodic preventative maintenance program that shall be adopted during the 

tunnelling operation. A nominated person shall be responsible for ensuring 

compliance with all preventative maintenance procedures. 

The Contractor shall provide foams, polymers, bentonite or other conditioners as 

required stabilizing the tunnel face and maintaining earth pressure until 

discharge from the screw conveyor under all conditions described in the Contract 

Documents,. All conditioners shall be biodegradable and inert. 

PT324 

PT324.1 

PT324.2 

PT324.3 

PT324.4 

GENERAL TUNNELLING CONSTRUCTION REQUIREMENTS 

Perform tunnel construction to minimize movement of ground in advance of, 

around and above the tunnel; to control water and water inflow and attendant soil 

transport; and to minimize settlement, subsidence and heave of the ground 

surface, structures, and utilities above and close to the tunnel for ground 

conditions that are to be encountered as described in the Contract Documents. 

Conduct tunnelling operations in a controlled manner so that settlement action 

levels are not reached. 

Unstable Conditions Procedures 

Whenever there is a condition likely to endanger the excavation or adjacent 

structures, notify the Engineer immediately and perform work on a 24-hour a day 

basis, including weekends and holidays, until such condition is resolved and 

eliminated. 

Maintain clean working conditions inside the tunnel by continuously and promptly 

performing housekeeping to remove muck and grout spills, trash and other 

debris. 

Daily records 


Page 11 of 15



PT324.5 

PT325 

PT325.1 

PT325.2 

The Contractor shall provide Shift Reports to the Engineer, no later than 24 

hours following the shift worked, detailing work performed except where 

otherwise allowed or approved herein, and integrated with requirements 

specified elsewhere for erection of precast segments, cavity grouting, and 

permeation grouting including: 

a) Date, location, shift and beginning and ending face station. A manual check 

of the TBM face location shall be conducted on a weekly basis. 

b) List of personnel by name, classification, and function working that shift. 

c) List of the number and type of equipment, including amount of and reason 

for any idle or down time. 

d) List of all materials used in the work. 

e) For every TBM shove or stroke: 

i) Description of soil or bedrock materials being excavated, including 

boulders and volume of excavated materials using methods as 

mutually agreed when not otherwise specified. 

ii) 

Description of delays and down time longer than 10 minutes, including 

reason for delay. Include maintenance records identifying the 

component, component position or number and reason for 

replacement. 

iii) Description and locations of water inflows, ground loss and other 

events. 

iv) 

Cutter, pick teeth and muck system component changes, including time 

and date of replacement, cutter or component position or number, and 

reason for change. 

v) Rates of advance for each hour. 

vi) Hours of actual machine operating time for each shift. 

vii) Max thrust pressure for each shove. 

viii) Ring number at start and end of each shift. 

ix) Type, manufacturer and produce name and number of all ground 

conditioners used on each shift. 

x) Volume and pressure of grout pumped behind precast segments on 

each shift. 

Results of quality control tests including: 

a) Volume of conditioner used as applicable for EPBM operations 

b) Volume of slurry and slurry density, as applicable for SPBM operations 

GROUTING 

General 

“Primary Grouting” refers to the initial cavity grouting which takes place during 

shield shove using a constant pressure grout system. This shall be to a pressure 

that equates to the earth and hydrostatic pressure. 

Method Statement – Grouting 

The contractor shall submit to the Engineer for acceptance within 56 days of the 

award of contract a detailed Method Statement of the grouting procedures to be 

followed during the construction of the tunnel. These details shall include: mix 

design, constituents and testing procedures, pumping rates and pressures, 

means of gauging pressures at the point of injection, proof drilling pattern to be 

adopted. 


Page 12 of 15



PT325.3 

PT325.4 

Primary Grout Injection 

Primary grout shall be injected by positive displacement .Consideration shall be 

given to providing a ring main system with the incorporation of approved 

retarders and accelerators to control the setting of the grout. The grout pump 

system shall incorporate a safety pressure by-pass arrangement, with means of 

reading the grout pressure at the point of injection. 

Records 

Records at each stage of the grouting process shall be kept, to include quantity 

and pressure applied at each injection point. These records shall be submitted to 

the Engineer daily. 

PT325.5 

PT326 

PT326.1 

PT326.2 

PT326.3 

Grout Performance 

The minimum compressive strength requirement of the grout as measured from 

testing cylinders shall be: 1.5N/mm² at 24 hours. 

INSTALLION, MONITORING AND CONTROL FOR SEGMENTAL LINING 

Installation of Tunnel Lining 

a) Construct rings to correct line and grade, in true circular form to preserve 

the circularity of the tunnel. 

b) Select combinations of tapered segment rings to provide specific tunnel 

geometry, and for making corrections as necessary during construction. 

c) Inspect concrete segments and gaskets before transport into the tunnel. No 

damaged segments are to be taken in to the tunnel. 

d) Tighten bolts across the joints to ensure gasket compression in accordance 

with gasket manufacturer recommendations. 

e) Do not add packings or materials to circumferential joints to adjust line and 

grade unless approved by the Project Manager. 

f) Stagger radial joints in adjacent rings. Rings may be rotated one or two 

equidistant bolt locations to meet line and grade and curve requirements, 

provided that only T joints result between adjacent rings. 

g) Hangers for utility lines necessary for construction of the tunnel may be 

connected to concrete segments with the Designer’s approval and on 

completion of the driving of the tunnel shall fill the holes with a non-shrink 

cement mortar. 

h) The Contractor shall fill all the caulking grooves of the segments with a nonshrink 

sand/cement mortar to the satisfaction of the Project Manager 

i) The Contractor shall fill all bolt pockets and exposed lifting holes and grout 

holes with a non-shrink sand/cement mortar to the satisfaction of the Project 

Manager 

Monitoring of Segments 

The Contractor shall take measurements of the horizontal and vertical diameters 

for each tunnel ring following installation within the tailskin. Measurements shall 

be forwarded to the Project Managerr on a daily basis. 

Installation Tolerances 

a) Projection or lipping of a segment with respect to the adjoining segment 

shall not exceed 12mm on the inside face. 

b) The deviation from the true inside diameter of the completed ring shall not 

exceed ± 15mm. 


Page 13 of 15



PT327 

PT327.1 

PT327.2 

PT327.3 

PT327.4 

PT327.5 

PT327.6 

PT327.7 

PT328 

SURFACE DISPLACEMENT MONITORING 

The contractor shall submit to the Project Manager, at least 28 days prior to the 

commencement of tunnelling a method statement detailing his proposal for the 

monitoring and control of surface displacement in accordance with the contract. 

The Contractor shall carry out settlement assessments and submit these to the 

Project Manager for acceptance. Any facilities predicted to settle >5mm shall be 

subject to pre and post-construction condition surveys. 

Surface displacement monitoring for the construction of the bored tunnel shall be 

carried out to ensure that surface (vertical) settlement is limited to



PT329 

PT329.1 

PT329.2 

TEMPORARY ELECTRICAL SUPPLY FOR TUNNEL CONSTRUCTION 

The Employer has agreed to make available a supply of electricity to the 

Contractor for the Construction of the Works. Details of the proposed supply are 

described in Schedule 3 Clause 4 of the Works Information. The Contractor shall 

confirm that the supply will be in accordance with his requirements. If the supply 

is insufficient the Contractor shall make his own arrangements for the provision 

of alternative additional power requirements at his own cost. 

Emergency Generator: Furnish an emergency standby generator of such 

capacity and configuration as to automatically and instantly come on line in the 

event of a power failure, without interruption, and to operate ventilation, lighting, 

pumping, communications and other critical systems. 

PT330 

PT330.1 

PT330.2 

PT330.3 

PT330.4 

CONSTRUCTION TOLERANCES 

Tunnel Tolerances 

a) Tunnel shall be constructed to the alignment as defined in the Contract 

Document. 

b) Maximum tolerances allowed in respect of the departure of any point on the 

bored tunnel alignment from its designed centerline shall not exceed 

100mm horizontally and 50mm vertically. 

c) No ponding anywhere in the tunnel shall be deeper than 25mm. 

d) The maximum lipping between the edges of adjacent segments shall not be 

greater than 12mm 

e) The plane of each segmental ring shall not depart any point from the plane 

surface normal to the longitudinal axis by more than 12mm. 

f) The maximum and minimum measured diameter in any one ring shall be 

within 0.5% of the theoretical design diameter of the ring. 

Groundwater Ingress 

The water infiltration criteria is set out below. This criteria applies for the bored 

tunnel: 

a) The infiltration volume of water for the total length of tunnel shall not 

exceed 0.1 litre per hour per linear metre of nominal bore. 

As-Built Tunnel survey 

On completion of the tunnel construction the Contractor shall carry out an As- 

Built Tunnel Survey in the bored tunnel. The accuracy of the survey shall be to ± 

20mm for vertical and horizontal alignment. 

Timings of Surveys 

The As-Built Tunnel Survey shall be completed as soon as practical following 

the completion of the tunnel, the As- Built Survey data is to be finalized and 

submitted to the Project Manager prior to the final acceptance of the tunnel. 


Page 15 of 15


PT - Particular Tunnelling Specification - PT400 


PT400 SPECIFICATION DESIGN AND SUPPLY OF PRECAST CONCRETE 

SEGMENTAL TUNNEL LININGS FOR THE LEE TUNNEL AND THE ABBEY 

MILLS CONNECTOR TUNNEL .......................................................................... 2 

PT401 SUMMARY........................................................................................................... 2 


PT403 SUBMISSIONS TO BE MADE FOLLOWING THE AWARD OF CONTRACT .... 2 

PT404 PRODUCTS......................................................................................................... 3 

PT405 DESIGN ............................................................................................................... 6 

PT406 CONCRETE FOR SEGMENTAL TUNNEL LINING ............................................ 9 

PT407 TESTING CONCRETE FOR SEGMENTAL LININGS......................................... 9 

PT408 QUALITY............................................................................................................ 11 

PT409 GENERAL CONSTRUCTION REQUIREMENTS.............................................. 13 

PT410 SEGMENT CASTING ........................................................................................ 17 

PT411 SITE QUALITY CONTROL................................................................................ 18 

PT412 TOLERANCES................................................................................................... 19 

PT413 ADJUSTMENTS AND REPAIR PROCEDURES............................................... 20 

PT414 INSPECTION OF PRECAST CONCRETE SEGMENTS .................................. 20 

PT415 DEMONSTRATION RINGS............................................................................... 20 

PT416 PRODUCT DELIVERY, STORAGE, AND HANDLING ..................................... 21 

PT417 SEQUENCING AND PROGRAMMING ............................................................. 22 

PT418 QUALITY ASSURANCE .................................................................................... 22 


Page 1 of 23



PT400 SPECIFICATION DESIGN AND SUPPLY OF PRECAST CONCRETE 

SEGMENTAL TUNNEL LININGS FOR THE LEE TUNNEL AND THE ABBEY 

MILLS CONNECTOR TUNNEL 

PT401 

SUMMARY 


materials, tools, equipment and incidentals necessary for the design, 

manufacture and supply of the precast concrete segmental tunnel lining for the 

bored tunnels as in accordance with the Works Information and Site Information. 

PT402 


PT402.1 BS EN 1992: 2004. Eurocode 2 : Design of Concrete Structures 

PT402.2 BS EN 14889-1:2006 Steel Fibres – Definitions, Specifications and 

Conformity. 

PT402.3 BS EN 206-1: 2000 Concrete, Specification, Performance 

8500-1:2006. Production and Conformity 

PT402.4 BS EN 8500-2: 2006 Specification for Constituent Materials and 

Concrete 

PT402.5 BS EN 934 parts 2 and 6. Admixtures for Concrete 

PT402.6 BS8666 Reinforcement, Dimensioning Bending and Cutting of Steel 

Reinforcement for Concrete 

PT402.7 BS 8110-Parts 1, 2 &3. Structural Use of Concrete 

PT402.8 BS8007:1987 Design of Concrete Structures for Retaining 

Aqueous Liquids 

PT402.9 British Tunnelling Society Specification for tunnelling 2000 

PT402.10 Concrete Society Technical Report No. 63 Guidance for the 

Design of Steel Fibre Reinforced Concrete 

PT402.11 EN 14651 2005 

Test Method for Metallic Fibred Concrete- 

Measuring the Flexural Tensile Strength 

(Limit of Proportionality (LOP), residual) 

PT402.12 EN 14721 2005 Test Method for Metallic Fibre Concrete – 

Measuring the fibre content in fresh and 

hardened concrete 

PT402.13 EN 14845-2 2006 Test Methods for Fibres in Concrete – Part 2: 

Effect on Concrete 

PT402.14 EN 14650 2005 Pre-Cast Concrete Products – General rules 

for factory production control of metallic fibred 

concrete 

PT403 

PT403.1 

SUBMISSIONS TO BE MADE FOLLOWING THE AWARD OF CONTRACT 

Product data 

At least 60 days prior to the beginning of segment production, the Contractor 

shall submit to the Project Manager the following information: 

a) Concrete mix proportions including the ingredients, water tests, trial mixes, 

and the results of all concrete tests. 


Page 2 of 23



PT403.2 

PT403.3 

PT403.4 

PT404 

PT404. 1 

b) Methods for testing and data to show that the proposed consolidation and 

curing process shall result in pre-cast concrete segments with the specified 

strengths and water permeability properties. 

c) Material specifications for components of the joint connection system and 

specifications describing the pullout capacity, material properties of the 

assemblies, and methods to verify proper assembly during installation in 

tunnel. 

d) Repair Mortar: Certificates of compliance with the properties listed herein 

and certifying the single source manufacturer for all compounds. 

Segment Design Submission 

The Contractor shall submit to the Project Manager for his acceptance within 28 

days of the award of contract calculations and drawings of the proposed 

segmental lining. The design submissions shall include as a minimum details of 

design standards used, loading conditions, design assumptions, design of the 

proposed radial and circumferential joint connection detail (including any 

alignment locating dowel), design parameters, method of analysis, geotechnical 

parameters, references and detailed drawings. 

Installation and inspection data 

At least 30 days prior to the beginning of segment casting operations, submit the 

following: 

a) Segment repair and rejection criteria. 

b) Submit a quality control programme which shall establish a comprehensive 

inspection and testing programme, including proposals for the 3D laser 

dimensional checking of cast segments and moulds to ensure compliance 

with the specification. This programme shall be described in detail in a 

quality assurance plan. 

Performance reports and test data 

a) Joint Connection Test Assemblies: Perform three certified tests by a suitably 

qualified UKAS certified independent laboratory to demonstrate the pullout 

capacity of the individual joint connector assemblies. These tests shall 

include the actual joint connector assemblies and shall be performed in the 

embedded condition using concrete of the design strength. 

b) Submit details and results of joint connection pull-out capacity testing at least 

30 days prior to the beginning of segment casting. 

c) During segment casting operations, submit on a weekly basis, methods and 

results of concrete testing for review and approval as specified herein. 

d) Product certifications 

On completion of the design of the TBM and the precast concrete segments, the 

Contractor shall provide written certification that the precast concrete segments 

are compatible with the proposed TBM. This shall include written certification by 

the precast concrete segment manufacturer, the Designer and the TBM 

manufacturer affirming the compatibility of the TBM and the liner system. 

PRODUCTS 

General 

All materials supplied to the Works shall conform to one or more of the following 

in the order of priority as detailed below 

a) This Specification 


Page 3 of 23



PT404. 2 

PT404. 3 

b) The appropriate European or British Standard. Where a BSI Kite Mark 

certification is available, material supplied shall be marked with the BSI 

Certification trade mark(kite mark) 

c) Materials where no standard readily applies shall be supplied as far as 

practically possible from a Quality Assured source and documentation to 

indicate compliance with the Specification shall be provided to the Project 

Manager 

d) All materials shall be handled and stored in a way to maintain their integrity 

and to avoid damage and degradation 

Concrete for Precast Concrete Tunnel Lining 

a) The Contractor shall provide for acceptance by the Project Manager all 

details of the mix design, source, details of materials and methods of 

production in advance of production. 

b) The production control of the factory producing pre-cast concrete segments 

shall be in accordance with EN 14650. 

c) The maximum size of aggregates shall be chosen to suit the proposed 

reinforcement together with the bolt pockets and grout hole inserts. 

d) Admixtures containing calcium chloride shall not be allowed. Unless 

otherwise agreed with the Project Manager any admixtures shall comply 

with the following:- 

i) BS EN 934-2. Admixtures for concrete, mortars and grouts – Part 2; 

Concrete admixtures – Definitions, Specifications and Conformity 

Criteria. 

ii) BS EN 934 – 6 - Quality Control. 

e) Admixtures shall be used in accordance with the manufacturer’s 


Reinforcing Steel 

a) Bar Reinforcement 

i) Reinforcement shall comply with BS4449 and BS8110. 

ii) Reinforcement shall be obtained from a certified supplier and the 

Contractor shall provide copies of the manufacturer’s certificates of test 

results relating to the steel reinforcement to be supplied. 

iii) Steel reinforcement shall be cut and bent in accordance with BS8666. 

iv) Steel Fibre reinforcement shall comply with BS EN 148899-1:2006 

Fibres for concrete steel fibres – Definitions, Specifications and 

Conformity, or as agreed by the Project Manager. 

b) Steel Fibre Reinforcement 

i) Steel Fibre shall be deformed steel fibre Group 1 in accordance with 

BS EN 14889-1. Fibre shall be produced from cold drawn wire. 

ii) 

Fibres may be collated with a fast-acting water-soluble glue, or may be 

uncollated individual fibres. 

iii) Fibres shall be stored in dry sealed containers until required for use 

and shall be free from corrosion, oil, grease, chlorides and deleterious 

materials which may reduce the bond between the fibres and the 

concrete. 

iv) Fibres shall be hook ended or deformed of minimum diameter 0.45mm 

and minimum tensile strength 1000 N/mm2. 

v) Fibres shall be of low carbon content conforming to BS EN 14889-1 


Page 4 of 23



PT404. 4 

PT404. 5 

PT404. 6 

PT404. 7 

PT404. 8 

PT404. 9 

vi) Fibres shall have an aspect ratio in the range of 40 to 80 for lengths of 

30 to 90mm. Tolerances shall be in accordance with BS EN 14889-1 

vii) Fibre type shall be selected on the basis of compliance with this 

Specification and on suitability and ease of use in the batching, mixing 

and concrete placement processes proposed, as demonstrated by site 

trials 

viii) Fibres which tend to form fibre balls during batching and mixing shall 

not be used. 

ix) 

Minimum fibre dosage rates for the concrete mix design shall be based 

upon the following table 

c) Minimum Steel Fibre Dosage 

Aspect Ratio 40 45 50 55 60 65 70 75 80 

Minimum Dosage (kg/m3) 65 50 40 35 30 25 20 20 20 

d) Tests on steel fibre shall be in accordance with BS EN 14721 and EN 

14845-2 

Grommets for precast concrete linings shall be PTFE unless otherwise approved 

by the Project Manager. 

Threaded Lifting Inserts shall be corrosion resistant. Type and size to be 

determined by Contractor based on handling and placing requirements. 

Grout holes shall be threaded and fitted with non-return valves designed and 

installed to resist twice the maximum grouting pressure. The maximum grouting 

pressure for design purposes shall be 8Bar or to the maximum hydrostatic 

pressure. Grout holes will be provided with threaded caps designed and tested to 

the maximum hydrostatic pressure. 

Gaskets 

Segments shall be supplied with waterproofing EPDM gaskets, or similar 

approved on all mating faces, complying with the requirements of this Contract 

as specified in Section PT500 

Dowels 

a) Alignment dowels shall be polyethylene material with shore hardness ASTM 

D785.D Scale 85 to 95. 

b) Circumferential Joint Dowel Connector 

The Circumferential joint dowel connectors, if proposed by the Contractor, 

shall be chosen to ensure the installed system is compatible with 

maintaining the gasket fully compressed. The Contractor shall provide the 

Project manager with load elongation test data to demonstrate the capacity 

of the dowel. 

Compression Packing 

Bituminous fibre-board compression joint packers or other material accepted by 

the Project Manager shall be provided to produce a maximum 3mm joint gap 

thickness. The gaskets shall be designed to allow full closure of gaskets with 

compression packing in place. The compression packing shall extend no closer 

than 6mm from inside edge of gasket groove, no closer than 50mm from corner 

of segments, and shall be the same width as the flat surface of the joint (less the 

6mm clearance). The compression packing shall cover a minimum of 90% of the 

area of the flat joint surface. 

PT404. 10 Radial and Circle Mechanical Joint Connector Systems 


Page 5 of 23



The design of the radial and circle mechanical joint connector system shall take 

into consideration the Contractor’s method of working, procedure for the erection 

of the segments and the provision of any required locator system to assist in the 

a) Bolts shall conform to grade 8.8 to BS 3692:2001. 

b) Galvanised bolts shall be hot dip spun to BS729 

c) Minimum bolt size shall be 20mm diameter. 

d) Nuts and sockets shall conform to BS4320:1968 unless noted. 

e) Structural washers shall conform to BS4395:1969. 

f) Galvanize ferrous parts of bolting system to minimum coating designation in 

accordance with BS4291:1988. 

g) Minimum 200kN/m² embedded pullout capacity yield on circumferential joint 

and radial joint connector assemblies. 

PT404. 11 Mortar for Segment Repair 

Provide a proprietary cementitious repair mortar for the repair of concretes. 

a) Suitable for use on vertical and overhead areas. The mortar is to be suitable 

for vertical applications having thicknesses greater than 50 mm 

b) The mortar shall have properties (compressive strength, indirect tensile 

strength, E-Modulus, shrinkage and coefficient of thermal expansion, etc) 

that are compatible with the segment concrete.. 

c) Components. The cementitious mortar shall consist of factory proportioned 

and pre-bagged materials whose components conform to the following 

properties: 

d) Mortar shall not contain chlorides, nitrates, added gypsum, added lime, or 

high alumina cements. Application time (working time) for horizontal and 

vertical repairs shall be 45 minutes after mixing and shall have set times 

suitable for the repair work in hand. Colour of the finished material shall be 

concrete grey. 

PT405 

PT405. 1 

PT405. 2 

DESIGN 

The Contractor shall be responsible for the design of the segments. 

All designs shall be carried out in accordance those Reference Standards as 

specified in this section and PT402 

a) All Technical Submissions have to be checked and approved by a qualified 

Chartered Engineer experienced in the design of tunnel segments. 

b) The design life of Tunnels shall be 120 years. 

c) Bolted linings shall be provided with a caulking groove to all sides of the 

segment. All bolts shall be grommeted or as accepted by the Project 

Manager. 

d) Segments shall be provided with recesses to accommodate a gasket in 

accordance with the Particular Specifications. Alternatively, gaskets may be 

fitted into a groove in the segment mould walls and cast into the segment 

with the freshly placed concrete 

e) Lining design shall take into consideration measures to maximise the 

resistance to spalling in fires of the lining during the construction phase. 

Such measures may include the use of monofilament polypropylene fibres 

with a mean diameter



with BD/2/05 of the Highways Agency DMRB for Technical Approval of 

Highway Structures. A Check Certificate will be submitted to the Project 

Manager, prior to any segments being cast, confirming that the proposed 

design has been carried out in accordance with the Contract requirements. 

g) Precast segmental lining systems shall be designed in accordance with 

Eurocode and environmental exposure conditions as defined in BS EN 

8500-1 2006 are as stated below. It should be noted that BS EN 8500-1 

does not provide guidance in the durability of steel fibre reinforced concrete, 

nor specifically for structures with a design life in excess of 100 years. The 

mix design shall comply with the following requirement:- 

• Water Permeability of concrete at 8Bar pressure 1 x 10⎯¹² m/s 

h) Summary of Exposure classes 

Location Exposure class Comment 

Internal XC3/4 Moderate humidity or cyclic wetting and 

drying 

External XD2 Wet rarely dry 

i) Summary Design Sulfate and ACEC Classes. 

Location 

Internal 

(worst 

case) 

Internal 

(best case) 

Design Sulfate 

Class 

ACEC class 

Comment 

DS-3 AC-5 Brownfield site with mobile 

ground water assumed 

DS-2 AC-4z Brownfield site with mobile 


External DS-2 AC-2 Brownfield site with mobile 


j) Summary of DC Classes 

Location DC class/ no. of APMs Comment 

Internal 

(worst case) 

Internal 

(best case) 

DC-4z / 1 Only APM3 – surface 

protection is recommended 

DC-4z / 0 - 

External DC-2 / 1 Additional APM applied due 

to potentially high hydrostatic 

head. 

k) Summary of code requirements for steel fibre reinforced lining 

The following table present the summary of the durability requirements to 

BS 8500 and BRE Special Digest 1:2005 

Parameter 

Exposure Case 

Requirements 

Internal 

(worst case) 

Internal 

(best case) 

External 

Strength Class 

(from design 

C50/60 C50/60 C50/60 


Page 7 of 23



PT405. 3 

PT405. 4 

PT405. 5 

assumptions) 

Max w/c ratio 0.45 0.45 0.40 

Cement type 

Minimum 

cementitious 

content (kg/m3) 

Max aggregate 

size (mm) 

Minimum CFBO 

cover (mm) RC 

Required 

minimum fibre 

dosage 

Testing 

Requirements 

Groups 1, 2 or 

3* 

Groups 1, 2 or 

3* 

380 380 380 

20 20 20 

n/a n/a n/a 

25kg/m3 

fibres 

steel 

Fibre content, 

Residual flexural 

strength, 

compressive 

strength, 

Indirect tensile 

strength 

Notes: 

For cement types refer to Table A.17 in BS 8500 

* Excluding Portland-limestone cement 

25kg/m3 

fibres 

steel 


Residual flexural 

strength, 

compressive 

strength, 


strength 

Groups 2 or 3 

25kg/m3 steel 

fibres 


Residual 

flexural 

strength, 

compressive 

strength, 


strength 





limited to, handling, erecting, jacking, and grouting. 

The Contractor shall confirm in writing that the tunnel rings are designed to 

negotiate the Contract alignment. 

a) The Contractor shall design and select lifting inserts for the segments that 

shall be compatible with the Contractor’s proposed segment lifting, handling, 

and erection equipment. 

The Contractor shall design for all construction-imposed, operational and testing 

loads, including, but not limited to the following: 

a) Loads across joint connections and along the circumference, to maintain 

joint and installation performance. 

b) Invert loads along the longitudinal axis of tunnel derived from transport of 

equipment and materials. 

c) Loads generated by grouting, handling and erection and the tunnel boring 

machine. 

d) Lifting devices shall be designed to handle the segment weight, including 

dynamic and impact stresses induced during the lifting, transport and 

placement of segments. 

e) Maximum internal loading generated when the tunnel is being used for 

storage of surcharge flows, including chemical attack. 


Page 8 of 23



f) Maximum internal loading generated when the tunnel is being tested as part 

of the pre-acceptance tests. 

PT406 

PT406. 1 

PT406. 2 

PT406. 3 

PT406. 4 

PT406. 5 

PT407 

PT407. 1 

CONCRETE FOR SEGMENTAL TUNNEL LINING 

General 

Concrete shall be produced and assessed for conformity in accordance with BS 

EN206 and BS8500. Further testing required for fibre reinforced concrete shall 

be undertaken in accordance with EN 14651 2005 or other equivalent standards 

approved by the Project Manager. 

Cements 

a) Constituent materials shall be obtained from a supplier operating quality 

systems in accordance with BS EN ISO 9002. 

b) Cementitious materials shall be of the following designations to Table 6 of 

BS8500-1: 

i) IIB-V+SR(cement combinations with 25-35% pfa) 

ii) IIIA+SR (cement combination with 36-65%ggbs) 

Aggregates 

a) Aggregates shall conform to BS EN 12620 and PD6682. 

b) The moisture content of the aggregate shall be accurately and continuously 

monitored throughout the concrete production process by the use of 

moisture probes in the aggregates storage bins. Appropriate adjustment 

shall be made to the added water and batching weight for the aggregate. 

Water 

Mixing water shall comply with BS EN 1008 

Admixtures 

a) Admixtures containing chlorides or other corrosive agents shall not be used 

b) High Range Water Reducing (superplasticiser) and accelerating admixtures 

shall be employed to achieve the consistence and early strength 

development characteristics required. These admixtures shall comply with 

BS EN 934-2 and BS EN 934-6. 

TESTING CONCRETE FOR SEGMENTAL LININGS 

Concrete Mixes 

a) The design and quality control of mixes shall be carried out by the 

Contractor. 

b) If existing data on materials and properties of trial concrete mixes are not 

available, preliminary laboratory tests shall be carried out to establish the 

mixes to satisfy the specification with the available materials. 

c) Laboratory trial mixes shall be tested to determine the following properties 

of mixes proposed: 

i) Compressive strength 

ii) Indirect tensile strength 

iii) Free water/cement ratio 

iv) Consistency 

v) Plastic density 

vi) Water permeability 


Page 9 of 23



PT407. 2 

PT407. 3 

PT407. 4 

vii) Residual flexural strength 

d) Unless otherwise agreed with the Project Manager, field trial mixes shall be 

prepared under full-scale site conditions at least 35 days before the 

commencement of concreting and tested in accordance with BS 1881. 

e) The mixes shall be tested to determine the following properties: 

i) Compressive strength 

ii) Indirect tensile strength 

iii) Free water/cement ratio 

iv) Consistency 

v) Water permeability 

vi) Plastic density 

vii) Residual Flexural Strength 

Acceptable value for the limits of these properties shall be established 

during the trials which shall therefore be used to monitor the quality control 

of the mixes and set the standard of compliance. 

Evidence of Suitability 

a) For each mix, before making concrete for use in the works and whenever a 

change in the materials or mix proportions is proposed, suitability of the mix 

shall be established from historic records and/or laboratory trials. The 

supplier shall provide the following information: 

i) cement certificates 

ii) admixture data sheets 

iii) total chloride, sulphate and alkali values for mixes 

iv) target proportions of constituents 

v) results of relevant previous tests for the concrete 

vi) consistence loss with temperature and time 

vii) strength development curves at 20°C between 12 hours and 28 days 

and at the curing temperature of the concrete between 4 hours and 3 

days 

b) Trials will be undertaken and approved prior to concrete being placed in the 

permanent works 

Site Trials 

a) For each trial mix the following set of test specimens shall be made from 

each of 3 consecutive batches: 

i) cubes for compression testing at 28 days to BS EN 12390 

b) For fibre reinforced concrete trial mixes the following set of additional test 

specimens shall also be made from each of 3 consecutive batches: 

i) 3 beams for flexural testing at 28 days to EN 14651 

ii) 3 cubes/cylinders for indirect tensile strength testing at 28 day to BS 

EN 12390-6 

c) For one batch an additional 2 samples shall be made to permit water 

permeability to be tested at 28 days in accordance with BS EN 12390-8 

Control of Chloride and Sulphate Content of Mixes 


Page 10 of 23



PT407. 5 

PT407. 6 

PT408 

PT408. 1 

The chloride content class of the concrete shall be CI 0,20 in accordance with 

BS EN 206-1. The total estimated sulphate (SO3) content of the concrete mixes 

shall not exceed 3.7% by mass of cement. 

Control of alkali-aggregate reactivity 

Precautions against alkali reactivity shall be taken in accordance with BRE 

Digest 330. 

Concrete batching 

a) The concrete batching plant shall be of a wet-batch, planetary pan mixer 

type, or similar approved, with moisture monitoring probes (Hydronix or 

similar) installed in the pan mixer 

b) Batching shall be by weigh-batching equipment with measuring devices 

(e.g. load cells) for the weighing mechanism. The machines shall be 

checked and calibrated regularly, every 3 months. Calibration certificates 

shall be made available to the Project Manager. 

c) The batching plant shall be controlled by a computerised batching system 

that is capable of recording the as-batched weights and moisture contents 

of all constituent materials for each individual batch of concrete 

d) The water supply to the concrete mixers shall have a metering system to 

control and record the amount of water used. 

e) Admixtures shall only be introduced using purpose made dosing equipment 

accurately calibrated. 

f) Water shall not be added to concrete after it has left the mixer. 

g) Provisions for the heating of water and aggregates in cold weather shall be 

included in the concrete batching plant 

h) Where steel fibre reinforcement is added to the concrete mix, this shall only 

be introduced using purpose made and calibrated weighing and dosing 

equipment. 

QUALITY 

Quality Control 

a) The Contractor shall plan all quality management procedures in accordance 

with BS EN ISO9001 and carry out all quality control testing as required 

herein within laboratories accredited by UKAS or operating to an equivalent 

standard for such testing. Method statements shall be submitted for the 

following concreting operations: 

i) production and transport - to demonstrate adequate control of 

constituent materials, consistence, temperature and early strength 

development characteristics 

ii) placing and compaction - to demonstrate adequate precautions to 

avoid honeycombing, excessive blowholes and segregation 

iii) curing and protection - to promote early strength development and 

long-term durability, including the avoidance of thermal and plastic 

cracking 

iv) concrete testing - to confirm the required properties of the fresh and 

hardened concrete have been obtained, including in situ temperature 

and strength monitoring 

v) segment handling – to demonstrate adequate planning to minimise the 

risk of accidental damage and overstressing during, striking, moving 

and lifting 


Page 11 of 23



PT408. 2 

PT408. 3 

vi) 

remedial actions – to confirm that each non-conformity can be 

addressed and serviceability restored. 

b) Test specimens shall be compacted by vibration. The shape, manufacture 

and curing for each specimen type shall be in accordance with BS EN 

12390-1 and BS EN 12390-2 as follows: 

i) cubes 150mm 

ii) beams 150 x 150 x 550mm 

iii) cylinders 150mm in diameter and 300mm in length 

Testing of fresh concrete 

a) The consistence of every batch of concrete shall be determined at delivery 

and assessed according to the Identity criteria in BS 8500-1 

b) Weekly monitoring of the plastic density of the concrete shall be carried out 

in accordance with BS EN 12350-6 

c) For steel fibre reinforced concrete the fibre content shall be demonstrated 

by taking random samples of 5 litres of the concrete mix and separating out 

the fibres. The frequency of testing shall be 1 set of 3 samples per mixing 

unit per production shift. The fibres shall be collected, dried and weighed. 

The fibre content shall be deemed acceptable if the following are satisfied: 

i) The average fibre content from a set of 3 samples is greater than the 

design fibre content; and 

ii) No individual sample has a fibre content less than 80% of the design 

fibre content. 

Testing of hardened concrete 

a) Cubes 

i) One set of cube test specimens shall be made for each work shift or 

every 100m3 of concrete used (whichever is more frequent) for identity. 

ii) For fibre reinforced concrete, one set of cube test specimens shall be 

made for each work shift or every 100m3 of concrete used (whichever 

is more frequent). 

iii) 

For fibre reinforced concrete, one set of beam test specimens shall be 

made for each 1000 m3 of production. 

b) One set of test specimens shall, comprise: 

i) For cubes: 3 cube for compressive strength testing at 7 days and 3 

cubes for compressive strength testing at 28 days to BS EN 12390-3 

ii) 

iii) 

For beams: 3 beams for flexural strength testing at 28 days to EN 

14651. 

For cylinders: 3 cylinders for indirect tensile strength testing at 28 days 

to BS EN 12390-6. 

c) Additional cubes shall be made to confirm the compressive strength prior to 

demoulding and handling. Alternatively, a maturity monitoring system, 

utilising thermocouples, laboratory calibrated concrete maturity curves at the 

anticipated hydration and curing temperatures and analytical computer 

software may be used to accurately determine actual in-situ concrete 

maturity (and, consequently, compressive strength) of cast segments prior 

to demoulding. 

d) Cubes results shall be assessed using the Identity criteria in BS EN 206. 

e) The beam results comply with the specified flexural strength at first crack as 

defined in EN 14651 if the minimum flexural strength at first crack is greater 


Page 12 of 23



PT408. 4 

PT409 

PT409. 1 

or equal to 5.8 N/mm2 for all specimens and the toughness factor, Re3 is 

greater or equal to 63%. 

f) Alternative testing standards may be used with the agreement of the 

segment designer. 

g) The beam results comply with the specified residual flexural strength as 

defined in EN 14651 if the following is satisfied: 

i) The average residual flexural strength obtained from any 4 consecutive 

tests exceeds the characteristic residual flexural strength by 0.3 

N/mm2. 

ii) The residual flexural strength obtained from any individual test is not 

less than the characteristic residual flexural strength less 0.3 N/mm2. 

iii) The characteristic residual flexural strength is not less than 63%. 

h) The cube results comply with the specified tensile splitting strength if the 

following are satisfied: 

i) The average tensile splitting strength obtained from any 4 consecutive 

tests exceeds the characteristic tensile splitting strength by 0.3 N/mm² 

ii) The tensile splitting strength obtained from any individual test is not 

less than the characteristic tensile splitting strength less 0.3 N/mm² 

iii) The characteristic tensile splitting strength is not less than 3.9 N/mm². 

i) The failed specimens shall be checked to ensure the random distribution 

and alignment of the steel fibres to the satisfaction of the Project Manager. 

Should the fibre alignment or distribution be noticeably non-random so as to 

improve the results from the testing above, the tests shall be repeated. 

Durability Test 

Where required concrete shall be tested for durability properties at a nominal age 

of 28 days as described below. 

a) Absorption tests shall be carried out in the testing laboratory on 75mm 

diameter cores cut at an age of 24 to 28 days to enable the absorption tests 

to be carried between 28 to 32 days in accordance with BSI881 Part 122. 

where appropriate, tests may be carried out on 75mm x 75mm prisms cast 

for the purpose. The upper acceptance limit for absorption after 30 min shall 

be 3%. 

b) Tests to determine the penetration of water under pressure (“effective 

permeability tests”) shall be carried out in accordance with BS EN 12390-8. 

the average depth of penetration of two determinations shall not exceed 

20mm. The coefficient of water permeability shall be calculated and 

corrected to provide a water permeability at 8Bar pressure. 

GENERAL CONSTRUCTION REQUIREMENTS 

Workmanship 

a) Furnish segments to be mechanically connected across joint faces. Provide 

joint connection assemblies to facilitate structural performance, achieve and 

maintain maximum joint closure and required gasket compression, and 

assist in ring stabilization and ring circularity. 

b) Provide gasket grooves as on designer approved drawings. Design joint to 

prevent lipping, which forms outside of edge of gasket groove, from contact 

with opposing lip during erection and thrusting of adjoining ring to prevent 

damage and spalling. Joint surface upon or against which gasket may bear 

shall be smooth, free of spalling, fractures and imperfections that would 


Page 13 of 23



PT409. 2 

PT409. 3 

PT409. 4 

adversely affect performance of joint. Provide written verification that 

specified gasket groove load shall not be exceeded. 

c) Each segment shall include no less than one grout/lifting hole, with lifting 

insert and non-return valves. 

Identification of Segments 

a) Provide a positive means of identifying each segment, such as a bar code 

system or similar approved that is accepted by the Project Manager. 

Segment identification should indicate the following information 

i) Internal diameter of liners 

ii) Concrete specification 

iii) Segment type designation 

iv) Manufacturer’s name or initials, if made off-site 

v) Date of manufacture 

vi) Mould number 

b) Indicated joint designation on inside face of liner. 

c) Markings such as logos, trademarks and proprietary information, except 

panel identification markings, are prohibited on surfaces of tunnel liner 

segments. 

Surface Finishes 

a) Ensure that the maximum local irregularity on formed surfaces does not 

exceed rounded protrusion of 1mm. above the general concrete surface. 

b) If the extrados surface is not formed, it shall be finished with a steel trowel 

such that the maximum local irregularity does not exceed a rounded 

protrusion 3mm above the general concrete surface. 

Segment Moulds 

a) Fabricate steel moulds with machined steel mating surfaces to conform to 

the dimensions and tolerances indicated, ensure segments of common 

design and cast in different moulds are interchangeable. Joints are to be 

watertight and form surfaces shall be prepared to provide segments with 

finished surfaces free from irregularities. 

b) Provide moulds of special sizes and cross sections with metal thickness, 

reinforcement, stiffness and surface finish as required to form concrete 

surfaces smooth, free from irregularities and conforming to the required 

dimensions. 

c) Construct moulds for precast segment with smooth casting faces such that 

a true, sound concrete surface is formed. 

i) Mould Bottom 

• The bottom formwork shall be composed of a 10mm bent steel 

plate (skin), two side plates with laser cut radius, two front plates 

and frame supports for side and head walls. 

• The bottom shall be high precision machined on one length and 

one side to guarantee the tolerance of the angle of the longitudinal 

joint. 

• The whole bottom formwork is to be assembled or manufactured 

in a pre-made gauge or template, in order to guarantee the given 

tolerances, and to avoid torsions during welding works. 


Page 14 of 23



• Additional stiffeners will be included at any connection point of the 

machined sidewalls and heads of the mould. 

• Each mould shall be equipped, if required, with 4 electric vibrators, 

each (2 for the key); force calculated according the mould and 

concrete weight. 

ii) 

iii) 

iv) 

Side Walls 

The side walls exist of strong, machined steel plates with supports and 

stiffeners to avoid torsion. 

Production procedure: 

• Cutting of the rolled plate 

• Welding the supports and stiffeners 

• Stress release by heat treatment 590 - 620°C 

• Machining - machining shall be conducted on computer controlled 

turning and milling machines. 

• Assembly 

Mechanical Supports to the Side Walls 

The mechanical supports to open and close the side walls shall 

include: 

• Legs made of U or H profiles 

• Closing spindle with round or trapezoidal threads, secured by prestressed 

springs 

• To be operated easily by hand. 

• Geometrical adjustment with strong threads and double nuts, 

secured by additional nuts 

Heads 

Shall comprise of: 

• Strong machined steel plates with supports and stiffeners to avoid 

torsion. 

• Opening and closing with mechanic toggle lever. 

• Self centring with cones to the side walls. 

v) Connections of Side Walls to Heads 

vi) 


• Conical bush with threaded centre hole 

• Centring cone with fixing bolt to avoid deformation of the head 

during mould closing and fixing 

Covers 


• 2 no. mould covers with supports to the mould bottom 

• For easy handling the covers shall be equipped with pull back 

springs. 


Page 15 of 23



• If the covers are closed, the concrete can be filled into the mould 

through the remaining gap of approx. 400 mm. 

• To guarantee a perfect outer radius, the lateral parts of the covers 

shall be laser cut and the seal shall be integrated in an additional 

groove-profile, welded to the cover. 

• Closing and fixing of the covers to be by heavy bolts, to be closed 

by hand or with hydraulic wrench 

vii) Seals 

• Rubber seals shall be integrated in the side walls and the heads to 

seal the gap to the mould bottom. 

• Additional rubber profile shall be integrated into the side wall to 

seal any possible gap to the heads. 

• Integrated rubber seals shall be provided in the radius of the 

covers to seal the cover and the outer radius of the side wall and 

head during concrete placement and compaction. 

viii) Manufacturing Tolerances 

• The moulds shall adjusted to the required tolerances according to 

the segment design. 

• The steel segment moulds shall be manufactured to the following 

tolerances: 

Flatness of surface of machined side walls: +/- 0.3mm 

Flatness of surface of machined heads: +/- 0.3mm 

Outer radius: 

+/- 1.5mm 

Arc length: 

+/- 1.0mm 

• Mould width shall be adjusted by using a digital micrometer. 

Width: 

± 0.5mm 

Thickness: 

± 1.0mm 

d) Segments of common dimensions and cast in different moulds shall be 

interchangeable. 

e) Provide moulds with individual identifications to ensure that all segments 

cast are marked and fully traceable. 

f) Form mould joint surfaces to provide flat planes at the orientations shown in 

the Works Information. 

g) Make all inserts to mould bolt pockets, holes, grout holes, etc. of approved 

steel or material having a coefficient of thermal expansion similar to that of 

concrete. 

h) Provide steel templates, gauges, and 3D laser checking apparatus, as 

required, to enable the measurement of tolerances to ensure that each 

segment falls the maximum and minimum dimensions allowed. Keep 

suitably protected from damage and distortion, free from dirt and corrosion 

and ready for use in checking the segments as described hereinafter. 

i) Clean and coat mould with non-staining release agent before each reuse. 

j) Securely anchor mould inserts and embedded items to formwork. 

k) Check each mould prior to each production pour to ensure that the 

dimensional tolerances of each form are being maintained. The Contractor 


Page 16 of 23



shall submit details of the proposed methods to achieve this, such as 

matched line markings on the mould walls, prior to the commencement of 

production 

l) Keep a record of all the units cast in each form. Any mould that becomes 

distorted or which casts faulty units shall be withdrawn from service until it is 

proved to the satisfaction of the Project Manager to be corrected. 

m) Formed surfaces – Smooth form finish. 

n) Extrados face – Segment shall be finished by a steel trowel. Provide a finish 

smooth and free from blemishes and surface undulations greater than 3mm 

to ensure an adequate seal is achieved with the tail skin seal of tunnelling 

machine. 

PT410 

PT410. 1 

PT410. 2 

SEGMENT CASTING 

Segment Casting Preparation 

a) The maximum variation in the position of the reinforcing bars shall be 

+5mm. Except for internally at joint connectors, grout holes, and as 

otherwise shown, the minimum concrete cover over the reinforcement shall 

be 35mm. Cages shall be sufficiently rigid to prevent deformation during the 

manufacturing process. 

b) Reinforcement cages shall be kept clean and dry and stored in such a 

manner that no distortion occurs. 

c) Clean reinforcement of loose rust, mill scale, and other foreign material. 

d) Fix concrete spacers so that the reinforcement is held firmly in the correct 

position within the formwork with all the cover specified. The spacers shall 

be rigidly fixed to the reinforcement to prevent displacement. If the spacers 

are wired on, the ends of the wires shall be turned into the unit. 

e) Furnish concrete spacers made from the approved concrete mix for the 

segments, compacted and cured to the same standard as the segments, or 

from concrete of an equal or higher strength to that identified in this Section. 

Plastic spacers are not to be used. 

f) Saturate all spacers with clean water prior to use. Spacers shall not be 

allowed to dry out after being fixed to reinforcement cages before the 

concrete is cast. 

g) Check reinforcement cages and other embedments within each mould. 

Segment Casting 

a) Produce segments under enclosed plant controlled conditions with 

production areas protected against wind, rain, snow, dust and direct 

sunlight. 

b) The initial concrete placement temperature shall be less than 25°C and shall 

be no less than10°C. Thermocouples shall be cast into freshly cast 

segments to check maximum temperatures reached within the cast 

concrete. This shall be performed on at least two occasions per production 

shift. At no time should the maximum concrete temperature exceed 60 deg 

C. 

c) Protect all concrete from hot and cold weather at all times during production. 

d) Consolidate and work concrete into complete contact with forms and 

embedded items. Consolidate and work concrete into complete contact with 

forms and embedded items. Consolidate concrete adjacent to side forms 

and along the entire length of forms to ensure a smooth surface finish after 

stripping of formwork. Alternatively, the use of self compacting concrete 

(SCC) may be employed in the casting of the segments. 


Page 17 of 23



PT410. 3 

PT411 

PT411. 1 

e) Check the first segment cast in any form to confirm that the segment 

conforms to the required dimensions and tolerances. Thereafter as a 

minimum, two percent of the segments cast on each shift, not less than one 

segment per shift, shall be checked on a rotating form/mould basis to 

ensure that the dimensions and tolerances of the segments are maintained. 

3D laser checking equipment shall be used for this process and shall be 

carried out at a designated laser checking station within the segment 

factory. 

f) All units of the same type shall be interchangeable and the dimensions for 

each unit shown in the Works Information shall be accurately reproduced 

within the tolerances indicated in the Works Information. 

g) If an out-of-tolerance segment is found, do not use that segment in the work 

or any other segments from the form found to be out-of-tolerance. The 

segment mould shall be removed from the production line and checked for 

dimensions with a 3D laser checking system and then adjusted and reengineered 

until it is within tolerances. 

h) Verify that the segments have attained the characteristic strength prior to 

shipping by comparison with strength gain-maturity curves. Verify the results 

with cube test from concrete cured with the segments. 

i) The segments shall be delivered to the tunnel excavation sites in 

undamaged condition. No segment may be installed in the permanent works 

until it has attained its characteristic compressive strength. 

Curing 

Segments shall be cured in accordance with the provisions of Eurocode 2. 

a) If proposing heat curing, immediately after segments have been cast, place 

the forms in a sealed, curing chamber. 

b) Do not attempt to remove segments from forms until compressive strength 

as required by the design of the segments is attained, as determined by 

temperature matched curing of cubes or a maturity monitoring system. 

c) When the compressive strength required for demoulding is attained, allow 

the segments to cool slowly. Segments shall be pre-stored internally within 

the casting factory for a minimum of 24 hours after demoulding in order to 

mitigate the risk of cracking from thermal shock. The use of thermal 

blankets may be required to minimise the rate of heat loss from the stored 

segments in cold weather conditions 

d) Segments shall be taken directly to outside storage stockpiles after the 24 

hours pre-storage 

e) Any heat curing cycle to be used shall be designed to minimise the 

consumption of energy and maintain the peak temperature of hydration to 

below 60 deg C. The segments shall be examined immediately after striking 

for evidence of cracking or other damage. Cracks greater than 0.15mm shall 

be treated as a non-conformance. 

SITE QUALITY CONTROL 

Acceptance Tests 

a) Source Quality Control – Factory Tests 

i) Provide a written notice at least 30 days before starting manufacture of 

segments, to allow the Project Manager to inspect place of fabrication. 

Inspection by the Project Manager shall not relieve the Contractor of 

responsibility of furnishing material and workmanship meeting specified 

quality requirements. 


Page 18 of 23



ii) 

iii) 

When directed by the Project Manager as a check for manufacture, 

assemble and bolt up randomly selected segments for at least two 

quality control rings, per one hundred rings manufactured, to prove that 

outside surfaces of rings are coplanar and that tolerances of the 

completed rings meet specified requirements. 

Allow the Project Manager access to work areas, and provide sufficient 

office space, workers, and equipment for performing the inspections. 

iv) Provide equipment including master working templates, gauges and 

callipers adequate to determine accuracies and tolerances in 

manufacture. 

b) Test concrete in accordance with the following requirements: 

i) Mix Design and Curing Strength Test. 

ii) Before start of manufacture, establish concrete mix that shall produce 

concrete of specified characteristic compressive strength. 

iii) After approval of the initial mix design has been obtained, make six 

cubes from a single batch of concrete. 

iv) Obtain prior written acceptance from the Project Manager for change in 

mix design during manufacture of segments. 

v) Prepare cubes before start of manufacture. Remove in pairs at 

appropriate time intervals during curing, and test for compressive 

strength immediately upon removal to establish correct curing duration. 

vi) For cubes prepared because of change in mix design, and as required 


c) Follow same procedures specified for cubes prepared before start of 

manufacture. 

d) Obtain acceptance of test results from the Project Manager before 

manufacture of segments using a new mix design. 

e) Production Test Cubes 

i) Prepare three cubes and cure as specified for each work shift or for 

every 100 mtrs³ of concrete used, whichever is more frequent. 

ii) 

Test cubes for compressive strength as follows: one cube after 7 days 

and the remaining 2 cubes after 28 days. 

iii) During segment manufacture, prepare two cubes per week from a 

concrete batch utilized to cast segments and test the cubes to 

demonstrate minimum strength for form removal is being attained. 

Alternatively, an approved maturity measurement system shall be used 

to determine the actual in-situ strength of the concrete immediately 

prior to demoulding. Procedures for monitoring demoulding strength by 

this method shall be submitted to and approved by the Project 

Manager. 

PT412 

PT412. 1 

TOLERANCES 

Dimensional Tolerances of segments 

Dimensions of individual precast concrete segments shall be within the following 

tolerances:- 

a) circumferential length: ± 1.0mm 

b) thickness: ± 1.5mm 

c) width: ± 1.0mm 


Page 19 of 23



PT412. 2 

PT413 

PT414 

PT415 

PT415. 1 

d) bolt holes: size +1.0mm, -2.0mm 

e) bolt holes and dowel position ± 0.5mm 

f) sealing gasket grooves: depth ± 1.0mm 

g) sealing gaskets grooves: width ± 0.5mm 

h) longitudinal joints: in a ±- 0.3mm with a rate of deviation plane 

along the axis of the 

not exceeding 0.6mm/m 

i) tunnel (longitudinal) 

j) In a radial plane: 0.1mm with a rate of deviation 

not exceeding 1mm/m 

k) Circumferential faces 0.3mm from theoretical plane with 

rate of deviation not exceeding 

0.6mm/m 

l) Smoothness of other faces extrados face:- ± 1.5mm 

intrados face:- ±1.0mm 

m) mismatch of sealing groove ± 0.5mm 

at corners 

Demonstration Ring Tolerances 

a) Internal diameter : ± 0.2% ID or 6.0mm whichever is the 

greater 

b) lip between adjacent segments



PT415. 2 

PT415. 3 

PT416 

PT416. 1 

PT416. 2 

concrete segmented rings erected vertically, without gaskets and packers, on a 

flat level base. 

a) Furnish to the Project Manager a 15-day written advance notice of start of 

assembly of demonstration liners. 

b) Assemble entire demonstration liner rings at the Site or another approved 

location above ground, with longitudinal axis vertical to demonstrate the 

accuracy of segments within the allowable tolerances. 

c) Furnish all tools and equipment to measure the required dimensions at no 

additional cost to the Project Manager. 

d) If demonstration liners are not acceptable, dismantle liners, adjust forms, 

cast new segments if necessary, and erect (at no additional cost) new 

demonstration liners for approval. Discard all segments that are determined 

to be unacceptable. 

e) Maintain demonstration liners intact for use as master rings in tolerance 

measurement until tolerances of completed rings are verified and the 

Project Manager authorizes removal of liners. Use dismantled segments for 

lining tunnel, if accepted by the Project Manager. 

Second Demonstration Ring 

A second full scale demonstration mock-up shall be erected at the place of 

manufacture of the TBM. The purpose of the mock-up is to verify compatibility 

between the TBM and the segments. 

a) Furnish to the Project Manager a 15-day written advance notice of start of 

assembly of demonstration liners at the TBM manufacturer’s plant. 

b) Erect one complete ring, with the longitudinal axis horizontal, utilizing the 

erector arm of the TBM. 

c) Provide supplemental framing and bracing as required to enable the 

erection of the lining. 

d) Disassemble ring once the demonstration assembly is complete and the 

Project Manager is satisfied with the compatibility of the erector arm and the 

segments. 

e) Undamaged segments of the demonstration liner may be utilized for the 

tunnel lining. 

f) Transport segments between the segment manufacturer’s plant and TBM 

manufacturer’s plant. 

Demonstration rings are to be erected on a flat and level base with the top ring 

rotated 180 degrees from the bottom ring with bolts inserted. All designed 

longitudinal packings shall be included in both rings. The test ring dimensions 

shall be checked to ensure that the tolerances are within the specification. 

PRODUCT DELIVERY, STORAGE, AND HANDLING 

Transportation 

Transport, store, and handle units to avoid damage and prevent excessive 

stresses from developing within segments. Follow all instructions from 

manufacturer of precast concrete segmental tunnel lining regarding 

transportation, storage, and handling of segments. 

Segment Support 

Use supports for storing and handling segments to avoid damage; do not subject 

segments to undue strains. 


Page 21 of 23



PT416. 3 

PT416. 4 

PT416. 5 

PT416. 6 

PT416. 7 

PT416. 8 

PT416. 9 

PT417 

PT417. 1 

PT418 

PT418. 1 

PT418. 2 

PT418. 3 

PT418. 4 

Prevent damage to segment surfaces during handling and storage. Keep wire 

ropes, chains and hooks from direct contact with segment surfaces, joint 

assemblies, gaskets and joint compression packings. 

Do not store segments with gaskets out-of-doors more than 90 days, unless the 

gaskets are proven to be resistant to ultra violet light and weather. 

During cold weather, prevent water from filling the pockets and recesses of the 

segments and freezing. 

Ensure segments have attained the specified 28-day characteristic strength prior 

to shipment. Segments to be loaded and shipped shall be a minimum 7 days old. 

Unless otherwise agreed with the Project Manager 

Inspect the segments, remove defective or damaged segments, and repair any 

minor damage, in accordance with specified procedures prior to loading 

segments. 

Arrange deliveries to the site from either the plant or stockpile. 

Pre-bagged Repair Mortar Products: 

a) Deliver materials to the site in original packages or containers bearing the 

manufacturer’s labels and identification. 

b) Store and handle materials to prevent inclusion of foreign matter and water 

deteriorating effects of hot and cold temperatures as prescribed by the 

manufacturer of the materials to prevent inclusion of foreign matter and 

water and deteriorating effects of hot and cold temperatures as prescribed 

by the manufacturer of the materials. 

c) Any material stored past the expiration date shall be disposed of properly. 

SEQUENCING AND PROGRAMMING 

The Contractor shall ensure availability of demonstration lining rings in the 

appropriate time frame to allow supplying completed rings to the manufacturer of 

the tunnel boring machine (TBM) for use in performance testing of the TBM as 

specified in PT200. 


Contractor Qualifications 

For the manufacture of the segments employ a qualified firm or personnel 

regularly engaged in the manufacture of high precision precast concrete units of 

similar dimensions and tolerances to those specified, and who has manufactured 

precision precast concrete units to the quality as specified in this Section and 

shall demonstrate at least 5 years experience in manufacture and distribution of 

high precision products. 

Personnel Qualifications 

Employ supervising personnel experienced in the manufacturing and installation 

of mechanically connected precast concrete segmented linings, to the 

satisfaction of the Project Manager. The supervising personnel shall have at 

least 2 years experience in the manufacturing and installation mechanically 

connected precast concrete segmented linings. 

Designer Qualifications 

All calculations shall be signed by a qualified Chartered Engineer in accordance 

with Schedule 6 of the Works Information. 

Test Agency Qualifications 


Page 22 of 23



Employ a Testing Laboratory, accepted by the Project Manager, to provide 

specified inspection and testing. The Testing Laboratory shall be UKAS 

Accredited and accepted by the Project Manager, unless otherwise instructed by 



Page 23 of 23




PT500 SPECIFICATION FOR EPDM GASKETS FOR PRECAST CONCRETE TUNNEL 

SEGMENTAL LININGS .......................................................................................... 2 

PT501 SUMMARY .............................................................................................................. 2 

PT502 REFERENCE STANDARDS ................................................................................... 2 

PT503 SUBMITTALS .......................................................................................................... 2 

PT504 MATERIALS ............................................................................................................ 2 

PT505 GENERAL................................................................................................................ 5 

PT506 INSTALLATION ....................................................................................................... 5 


Page 1 of 5



PT500 

PT501 

PT502 

PT503 

PT503.1 

PT503.2 

PT503.3 

PT503.4 

PT504 

PT504. 1 

SPECIFICATION FOR EPDM GASKETS FOR PRECAST CONCRETE 

TUNNEL SEGMENTAL LININGS 

SUMMARY 

The work of this Section includes, but is not limited to providing all labour, 

materials, tools, equipment, and incidentals necessary for EPDM gaskets for 

precast concrete tunnel linings for the Thames Lee Tunnel and the Abbey Mills 

Connection Tunnel, in accordance with the Works Information. 


BS2494 Type D 

SUBMITTALS 

The Contractor shall submit the following to the Project Manager for acceptance. 

a) Details of proposed gasket 

b) Manufacturer’s name, address etc. 

c) Name of proposed proprietary system 

d) Details of proposed gasket 

e) Details of gasket adhesive if used 

f) Details of gasket lubrication. 

g) Case Studies detailing previous relevant applications of the system 

Manufacturer’s Qualifications 

The manufacturer of the EPDM gaskets shall have been regularly engaged in the 

manufacture of such products for tunnels with hydrostatic heads equal to or 

greater than that of this scheme for a period of no less than 5 years and shall 

submit documentation to verify this. 

Manufacturer’s Installation Recommendations for: 

a) Storage 

b) Handling 

c) Installation 

d) Testing 

e) Repair Instructions 

f) Special instructions for corners and intersections. 

g) Installation equipment if any 

h) Health and safety data 

Shop Drawings, including as a minimum: 

a) Layout of EPDM gasket detailing joint locations. 

b) Details of joints and other construction details. 

MATERIALS 

Elastomeric Gaskets – General 

a) ‘Ethylene-Propylene-Diene-Monomer’ materials are referred to using the 

acronym EPDM. 


Page 2 of 5



PT504. 2 

b) Elastomeric gaskets shall be from approved manufacturers and shall be 

tested in accordance with the Works Information, to the acceptance of the 

Project Manager. Gaskets shall be dense elastomeric synthetic rubber type, 

free of pittings, porosity, blisters and other imperfections, manufactured as a 

continuous frame, with moulded gasket corners mitred on each side and 

vulcanized to provide uniform gasket thickness along the entire length of 

mating surfaces. 

c) The extruded section shall be joined to form a rectangular gasket that is 

stretch fit into the grooves of the concrete segments. The corner joint shall 

be shot moulded and the corner pieces shall be of a different section from 

the extruded lengths in order that the water tightness characteristics 

described in this Section may be achieved and to avoid excessive load on 

the corners of the concrete segments. 

d) Gaskets shall be manufactured from extruded solid sections with 

appropriate spaces within the section to enable the gasket to be fully 

compressible within the groove formed in the concrete segments. 

e) The material from which gaskets are to be manufactured shall withstand any 

chemical attack from the ground or groundwater and shall not be subject to 

any biological degradation, to such an extent that the gasket fails to function 

properly during the specified warranty period for the gaskets as specified in 

this Section. 

f) The material shall consist of a compound based on EPDM able to withstand 

the long term stresses and strains without detriment to the specified 

performance. 

g) The gasket cross-section shall be dimensioned to suit the groove as 

detailed for the mating faces of the segmental tunnel linings in accordance 

with the Works Information and shall be approved by the tunnel segment 

designer. Manufacturing tolerances shall be in accordance with DIN ISO 

3302-2, tolerance class E2. 

h) The supplier shall confirm in writing that the gasket groove as dimensioned 

in the Works Information is correct for the proposed gasket. As a minimum 

the gasket shall be designed to withstand under full compression the 

maximum hydrostatic pressure with a factor of safety of 1.5. 

i) The supplier shall ensure that the performance of the gasket shall comply 

with all the requirements of the Contract. 

Elastomeric Gaskets - Testing and Material 

a) Gaskets shall be tested as follows. The test rig shall simulate a range of 

conditions of displacement and joint gap, including the worst combination to 

be encountered in the completed structure. In each test the water pressure 

shall be increased in increments of 1.0Bar and held at each value for 5 

minutes. The final pressure shall be at least two times in excess of the insitu 

maximum hydrostatic pressure to which the tunnel may be subjected. 

This pressure shall be maintained for 24 hours during which no leakage 

shall occur at the gasketed faces. Tests shall be carried out at normal 

ambient (surrounding) temperature. 

b) EPDM gaskets shall be in accordance with the following specified minimum 

requirements 

Value Standard Requirement 

Tensile strength ISO 30 

(ASTM D412) 

> 9mPa 

Elongation ISO 30 > 175% 


Page 3 of 5



Value Standard Requirement 

Hardness 

Short Term (22hrs 70°C) 

15% compression 

Long Term (70hrs 23°C) 20% 

compression 

(ASTM D412) 

ISO 48 

(ASTM D2240), 

Durometer A 

Ozone resistance ISO 1431-1 

(ASTM D1149, 

ASTM D518 Proc A). 

Accelerated ageing: 

ISO 188 

168 hours, 70°C 

(ASTM D573) 

80 ± 5 

International Rubber 

Hardness Degree 

(IRHD) 

No surface cracking 

of untensioned 

specimen under x7 

magnification 

• change of 

hardness less 

than -5 to +8 

(IRHD) 

• change of tensile 

strength less than 

-20% to +10% 

• change of 

elongation less 

than -30% to 

+10% 

Stress relaxation Test. 

Elevated temperature at 70°C 

for 3 months. 

Constant vertical deflection to 

uncompleted gap closure of 

3mm. 

60 minute measured load set 

equal to 100% 

Water absorption 

48 hours at 70 °C 

Use distilled water for 

standard test 

Oil absorption 

70 hours at 70 °C (IRM903) 

ISO 11346 

WLF Equation 

ASTM D471 

Use distilled water for 

standard test 

ASTM D471 

Minimum residual 

load to be better than 

55% after 3 months of 

continuous testing 

Change in weight less 

than 10% 

Change in weight less 

than 110% 

PT504. 3 

Warrantees and Guarantees 

a) Materials furnished and supplied under this Section shall be guaranteed to 

perform according to the Works Information and to the manufacturer’s 

published specifications whichever is greater or more stringent. 

b) The materials shall be warranted for a minimum of 50 years on-site against 

failures and defects in materials. 


Page 4 of 5



PT505 

PT505.1 

PT505.2 

PT506 

PT506.1 

PT506.2 

PT506.3 

PT506.4 

PT506.5 

GENERAL 

Technical Assistance 

A representative of the EPDM manufacturer shall be available at the Site, or at 

the segment manufacturing facilities, to provide installation and testing 

instructions to the Contractor’s or the Segment Manufacturer’s personnel if and 

when required. The EPDM manufacturer’s representative shall also provide 

training to the Contractor’s or the Segment Manufacturer’s personnel before the 

beginning the EPDM installation. 

General Competence and Workmanship 

The Contractor shall demonstrate to the satisfaction of the Project Manager, 

proven ability and competence to install the approved EPDM gasket in 

accordance with the manufacturer’s instructions. 

INSTALLATION 

Surface Inspection 

Surfaces to receive EPDM gaskets shall be inspected for defects which could 

result in poor performance of the gasket. Defects shall be corrected prior to the 

installation of the EPDM gasket. 

Preparation 

Surfaces to receive EPDM gaskets shall be cleaned and free of oil, water, 

laitance and other deleterious substances in accordance with the EPDM gasket 

manufacturer’s instructions. 

Adhesive 

The gasket shall be fixed into the groove cast in the segmental tunnel linings 

prior to erection using only adhesives recommended by the EPDM gasket 

manufacturer. The adhesive shall be non-toxic and non-flammable at 

temperatures up to 200°C 

Lubricant 

Gasket faces to the key segment radial joints shall be lubricated prior to segment 

erection with a product recommended by the EPDM gasket manufacturer and 

accepted by the Project Manager. The lubricant shall be an organic soap based 

and applied by brush. 

Fitting 

Fitting shall be in accordance with the EPDM gasket manufacturer’s instructions. 


Page 5 of 5




PT600 SPECIFICATION DESIGN AND SUPPLY OF PRECAST CONCRETE SHAFT 

SEGMENTAL LININGS FOR THE LEE TUNNEL PROJECT................................ 2 

PT601 SUMMARY .............................................................................................................. 2 

PT602 REFERENCE STANDARDS ................................................................................... 2 

PT603 SUBMISSIONS TO BE MADE FOLLOWING THE AWARD OF CONTRACT........ 2 

PT604 PRODUCTS............................................................................................................. 3 

PT605 DESIGN................................................................................................................... 5 

PT606 CONCRETE FOR SEGMENTAL SHAFT LINING................................................... 6 

PT607 CONCRETE MIXES ................................................................................................ 7 

PT608 QUALITY ................................................................................................................. 7 

PT609 SEGMENT CASTING............................................................................................ 10 

PT610 SITE QUALITY CONTROL.................................................................................... 11 

PT611 TOLERANCES ...................................................................................................... 11 

PT612 ADJUSTMENTS AND REPAIR PROCEDURES .................................................. 12 

PT613 PRODUCT DELIVERY, STORAGE, AND HANDLING......................................... 12 

PT614 QUALITY ASSURANCE........................................................................................ 13 


Page 1 of 13



PT600 

PT601 

SPECIFICATION DESIGN AND SUPPLY OF PRECAST CONCRETE SHAFT 

SEGMENTAL LININGS FOR THE LEE TUNNEL PROJECT 

SUMMARY 


materials, tools, equipment and incidentals necessary for the design and supply 

of the precast concrete segmental shaft linings for the Lee Tunnel Project in 

accordance with the Contractor’s design of the Permanent Works 

PT602 


PT602.1 ABS EN 1992: 2004 Eurocode 2 : Design of Concrete Structures 

PT602.2 ASTM 820/820M-04 A Standard Specification for Steel Fibres for 

Fibre Reinforced Concrete 

PT602.3 BS EN 206-1: 2000 Concrete, Specification, Performance, 

8500-1. Production and Conformity 

PT602.4 BS EN 8500-2: 2002 Specification for Constituent Materials and 

Concrete 

PT602.5 BS EN 934 parts 2 and 6 Admixtures for Concrete 

PT602.6 BS8666 Reinforcement, Dimensioning Bending and 

Cutting of Steel Reinforcement for Concrete 

PT602.7 BS 8110-Parts 1, 2 &3 Structural Use of Concrete 

PT602.8 BS8007:1987 Design of Concrete Structures for Retaining 

Aqueous Liquids 

PT602.9 British Tunnelling Society Specification for Tunnelling 2000 

PT602.10 Technical Report No. 63 Guidance for the Design of Steel Fibre- 

Reinforced Concrete 

PT603 

PT603.1 

PT603.2 

SUBMISSIONS TO BE MADE FOLLOWING THE AWARD OF CONTRACT 

Product data 

At least 60 days prior to the beginning of segment production, the Contractor 

shall submit to the Project Manager the following information: 

a) Concrete mix proportions including the ingredients, water tests, trial mixes, 

and the results of all concrete tests. 

b) Methods for testing and data to show that the proposed consolidation and 

curing process shall result in uncracked segments with the specified 

strength and permeability properties. 

c) Polymer Repair Mortar: Certificates of compliance with the properties listed 

herein and certifying the single source manufacturer for all compounds. 

Shaft Segment Design Submission 

a) The Contractor shall submit to the Project Manager for his acceptance in 

accordance with the timings as defined in Schedule 2 of the Works 

Information calculations and drawings of the proposed shaft segmental 

lining. The design submissions shall include as a minimum details of design 

standards used, loading conditions, design assumptions, design of the 

proposed radial and circumferential joint connection detail (including any 

alignment locating dowel), design parameters, method of analysis, 

geotechnical parameters, references and detailed drawings. 


Page 2 of 13



b) Joint Connection: If the proposed Shaft Segment joint connection design is 

an existing system the Contractor shall provide details of at least 3 projects 

where this system has been successfully used previously. Contact names 

and telephone contact numbers for a Reference for each project shall also 

be included 

c) During segment casting operations, submit methods and results of concrete 

testing for review and approval as specified herein. 

d) Product certifications 

Following the acceptance by the Project Manager of the Contractors 

proposed methods of construction, the Contractor shall provide written 

certification that the precast concrete segments are compatible with the 

proposed methods of Shaft construction. This shall include written 

certification by the precast concrete segment manufacturer and the 

Designer 

PT604 

PT604. 1 

PT604. 2 

PT604. 3 

PRODUCTS 

General 

All materials supplied to the Works shall conform to one or more of the following 

in the order of priority as detailed below: 

a) This Specification 

b) The appropriate European or British Standard. Where a BSI Kite Mark 

certification is available, material supplied shall be marked with the BSI 

Certification trade mark(kite mark) 

c) Materials where no standard readily applies shall be supplied as far as 

practically possible from a Quality Assured source and documentation to 

indicate compliance with the Specification shall be provided to the Project 

Manager 

d) All materials shall be handled and stored in a way to maintain their integrity 

and to avoid damage and degradation 

Concrete for Precast Concrete Shaft Lining 

a) Admixtures containing calcium chloride shall not be allowed. Unless 

otherwise agreed with the Project Manager any admixtures shall comply 

with the following: 

i) BS EN 934-2. Admixtures for concrete, mortars and grouts – Part 2; 

Concrete admixtures – Definitions, Specifications and Conformity 

Criteria. 

ii) 

BS EN 934 – 6 - Quality Control. 

b) Admixtures shall be used in accordance with the manufacturer’s 


Reinforcing Steel 

a) Bar Reinforcement 

i) Reinforcement shall comply with BS4449 and BS EN 10080:2005. 

ii) Reinforcement shall be obtained from a certified supplier and the 

Contractor shall provide copies of the manufacturer’s certificates of test 

results relating to the steel reinforcement to be supplied. 

iii) Steel reinforcement shall be cut and bent in accordance with BS8666. 

iv) Steel Fibre reinforcement shall comply with BS EN 148899-1:2006 

Fibres for concrete steel fibres – Definitions, Specifications and 

Conformity, or as agreed by the Project Manager. 


Page 3 of 13



PT604. 4 

PT604. 5 

PT604. 6 

PT604. 7 

b) Steel Fibre Reinforcement 

i) Steel Fibre shall be deformed steel fibre Group 1, 2 or 3 in accordance 

with BS EN 14889-1 except that Group 1 fibre may be either circular or 

rectangular in section. Fibre shall be produced from mild steel or cold 

drawn wire. 

ii) 

Fibres may be collated with a fast-acting water-soluble glue, or may be 

uncollated individual fibres. 

iii) Fibres shall be stored in dry sealed containers until required for use 

and shall be free from corrosion, oil, grease, chlorides and deleterious 

materials which may reduce the bond between the fibres and the 

concrete. 

iv) Fibres shall be hook ended or deformed of minimum diameter 0.45mm 

and minimum strength 1000 N/mm2. 

v) Fibres shall be of low carbon content conforming to BS EN 14889 or 

EN 10016-2-C9D 

vi) Fibres shall have an aspect ratio in the range of 40 to 80 for lengths of 

30 to 90mm. Tolerances shall be in accordance with BS EN 14889-1. 

vii) Fibre type shall be selected on the basis of compliance with this 

Specification and on suitability and ease of use in the batching, mixing 

and concrete placement processes proposed, as demonstrated by site 

trials 

viii) Fibres which tend to form fibre balls during batching and mixing shall 

not be used. 

c) Tests on steel fibre shall be in accordance with BS EN 14721 or ASTM 

A820-04) except that: 

i) The cross sectional area used to compute the tensile strength shall be 

carried out to four decimal places, in units of square millimetres, and 

shall be: “for drawn wire fibres, the area calculated from the actual 

diameter”. 

ii) 

For cut sheet fibres, the area calculated from the actual thickness and 

width, or if fibres are tested, the area of each individual fibre calculated 

from the measured length and weight of the fibre, weighed to the 

nearest 0.0001g, based on a density of 7850 kg/m³. 

iii) For melt-extraction fibres, the area calculated from the equivalent 

diameter of the fibres, computed from measured average length and 

the weight of a known quantity of fibres, based on a density 7850 

kg/m³. 

Spacers shall be concrete with a compressive strength similar to that of the 

segments. Plastic spacers may not be used 

Grommets for precast concrete linings shall be PTFE unless otherwise approved 


Threaded Lifting Inserts shall be corrosion resistant. Type and size to be 

determined by Contractor based on handling and placing requirements. Test 

certificates required. 

Grout holes shall be threaded and fitted with non-return valves designed and 

installed to resist twice the maximum grouting pressure. The maximum grouting 

pressure for design purposes shall the maximum hydrostatic pressure. Grout 

holes will be provided with threaded caps designed and tested to the maximum 

hydrostatic pressure. 


Page 4 of 13



PT604. 8 

PT604. 9 

PT604. 10 

PT604. 11 

PT604. 12 

PT605 

PT605.1 

PT605.2 

Gaskets 

Segments shall be supplied with EPDM gaskets on all mating faces complying 

with the requirements of this Contract as specified in Section PT500 

Dowels 

Circumferential Joint Dowel Connector 

The Circumferential joint dowel connectors, if proposed by the Contractor, shall 

be chosen to ensure the installed system is compatible with maintaining the 

gasket fully compressed. The Contractor shall provide the Project manager with 

load elongation test data to demonstrate the capacity of the dowel. 

Compression Packing 

Bituminous fibre-board compression joint packers or other material accepted by 

the Project Manager shall be provided to produce a maximum 3mm joint gap 

thickness. The gaskets shall be designed to allow full closure of gaskets with 

compression packing in place. The compression packing shall extend no closer 

than 6mm from inside edge of gasket groove, no closer than 50mm from corner 

of segments, and shall be the same width as the flat surface of the joint (less the 

6mm clearance). The compression packing shall cover a minimum of 90% of the 

area of the flat joint surface. 

Radial and Circle Mechanical Joint Connector Systems 

The design of the radial and circle mechanical joint connector system shall take 

into consideration the Contractor’s method of working, procedure for the building 

of the segments and the provision of any required locator system to assist in the 

process. 

a) Bolts shall conform to grade 8.8 to BS 3692:2001 and BS EN ISO 898-1 

b) Galvanised bolts shall be hot dip spun to BS EN ISO 1461:1999 

c) Minimum bolt size shall be 20mm diameter. 

d) Nuts and sockets shall conform to BS4320:1968 unless noted. 

e) Structural washers shall conform to BS EN 14399-1:2005 

f) Galvanize ferrous parts of bolting system to minimum coating designation in 

accordance with BS EN ISO 1461:1999 

g) Minimum 200kn/m² embedded pullout capacity yield on circumferential joint 

and radial joint connector assemblies. 

Mortar for Segment Repair 

An approved proprietary system shall be proposed by the Contractor for 

acceptance by the Project Manager 

DESIGN 

The Contractor shall be responsible for the design of the shaft segments. 

All designs shall be carried out in accordance those Reference Standards as 

specified in this Section and PT400. 

a) All Technical Submissions have to be checked and approved by a 

Chartered Engineer experienced in the design of shaft segments. 

b) The design life of Shafts shall be 120 years. 

c) Bolted linings shall be provided with a caulking groove to all sides of the 

segment. All bolts shall be grommeted or as accepted by the Project 

Manager. 

d) Segments shall be provided with recesses to accommodate a gasket in 

accordance with the Particular Specifications. 


Page 5 of 13



PT605.3 

PT605.4 

PT605.5 

PT605.6 

PT606 

PT606.1 

PT606.2 

PT606.3 

e) The Contractor shall appoint an Design Consultant, approved by the 

Project Manager, to carry out an independent CAT3 design check in 

accordance with BD/2/05 of the Highways Agency DMRB for Technical 

Approval of Highway Structures. A Check Certificate will be submitted to 

the Project Manager, prior to any segments being cast, confirming that the 

proposed design has been carried out in accordance with the Contract 

requirements. 

Precast segmental lining systems shall be designed in accordance with 

Eurocode and environmental exposure conditions as defined in BS EN 8500-1 

2006. It should be noted that BS EN 8500-1 does not provide guidance in the 

durability of steel fibre reinforced concrete. 


ground, water loads and environmental conditions on the completed tunnel. The 

Contractor shall ensure that the segments are compatible with its selected 


limited to, handling, erecting, jacking, and grouting. 

The Contractor shall design for all construction-imposed, operational and testing 

loads, including, but not limited to the following: 

a) Loads across joint connections and along the circumference, to maintain 

joint and installation performance. 

b) Loads generated by grouting, handling and erection and the tunnel boring 

machine. 

c) Lifting devices shall be designed to handle the segment weight, including 

dynamic and impact stresses induced during the lifting, transport and 

placement of segments. 

d) Maximum internal loading generated when the shaft is being used for 

storage of surcharge flows 

e) Maximum internal loading generated when the shaft is being tested as part 

of the pre-acceptance tests. 

At Abbey Mills the Contractor shall take due notice in his design of the shaft 

segments for the potential of contaminated ground at the Shaft A and Shaft F 

locations, details of which can be found in Schedule 6 of the Works Information 

and the Site investigation as included in the Contract. 

CONCRETE FOR SEGMENTAL SHAFT LINING. 

General 

Concrete shall be produced and assessed for conformity in accordance with BS 

EN206 and BS8500. Further testing required for fibre reinforced concrete shall 

be undertaken in accordance with Japan Concrete Institute Standard JC1 SF4 or 

other equivalent standards approved by the Project Manager. 

Water 

Mixing water shall comply with BS EN 1008 

Admixtures 

a) Admixtures containing chlorides or other corrosive agents shall not be used 

b) Water reducing and accelerating admixtures shall be employed to achieve 

the consistence and early strength development characteristics required. 

These admixtures shall comply with BS EN 934-2 and BS EN 934-6. 


Page 6 of 13



PT607 

PT607.1 

PT607.2 

PT607.3 

PT607.4 

PT607.5 

PT608 

PT608.1 

PT608.2 

CONCRETE MIXES AND CONCRETE TESTING 

Concrete Mixes and Testing. 

The design, testing and quality control of mixes shall be carried out by the 

Contractor in accordance with the requirements of PT400. 

Evidence of Suitability 

For each mix, before making concrete for use in the works and whenever a 

change in the materials or mix proportions is proposed, suitability of the mix shall 

be established from historic records and/or laboratory trials. 

Control of Chloride and Sulphate Content of Mixes 

The chloride content class of the concrete shall be CI 0,20 in accordance with 

BS EN 206-1. The total estimated sulphate (SO3) content of the concrete mixes 

shall not exceed 3.7% by mass of cement. 

Control of alkali-aggregate reactivity 

Precautions against alkali reactivity shall be taken in accordance with BRE 

Digest 330. 

Concrete batching 

a) Batching shall be by weigh-batching machines equipped with measuring 

devices for the weighing mechanism. The machines shall be cleaned, 

checked and adjusted regularly. Calibration records shall be made 

available to the Project Manager. 

b) The water supply to the concrete mixers shall have a metering system to 

control and record the amount of water used. 

c) Admixtures shall only be introduced using purpose made equipment 

accurately calibrated. 

d) Water shall not be added to concrete after it has left the mixer. 

e) Materials shall not be heated unless agreed with the Project Manager. 

f) Where steel fibre reinforcement is added to the concrete mix, this shall only 

be introduced using purpose made equipment. 

QUALITY 

Quality Control 

The Contractor shall plan all quality management procedures in accordance with 

BS EN ISO9001 and carry out all quality control testing as required herein within 

laboratories accredited by UKAS or operating to an equivalent standard for such 

testing. Method statements shall be submitted to the Project Manager for the all 

concreting operations: 

Testing of hardened concrete 

a) Cubes 

i) One set of cube test specimens shall be made for each work shift or 

every 100m3 of concrete used (whichever is more frequent) for identity. 

ii) For fibre reinforced concrete, one set of cube test specimens shall be 

made for each work shift of every 100m3 of concrete used (whichever 

is more frequent). 

iii) For fibre reinforced concrete, one set of beam test specimens shall be 

made for each week’s production. 

iv) Additional cubes shall be made to confirm the strength prior to 

demoulding and handling. 


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PT608.3 

PT608.4 

PT608.5 

v) Cubes results shall be assessed using the Identity criteria in BS EN 

206. 

vi) Beam results shall comply with the specified flexural strength at first 

crack as defined in JCI SF4 if the minimum flexural strength at first 

crack is greater or equal to 4.2 N/mm² for all specimens. 

vii) Alternative testing standards may be used with the agreement of the 


b) The beam results comply with the specified residual flexural strength as 

defined in EN14651 if the minimum flexural at first crack is greater or equal to 

5.8N/mm² if the following is satisfied: 

i) The average residual flexural strength obtained from any 4 consecutive 

tests exceeds the characteristic residual flexural strength by 0.3 

N/mm². 

ii) 

iii) 

The residual flexural strength obtained from any individual test is not 

less than the characteristic residual flexural strength less 0.3 N/mm². 

The characteristic residual flexural strength is not less than 3.0 N/mm². 

c) The cube results comply with the specified tensile splitting strength if the 

following are satisfied: 

i) The average tensile splitting strength obtained from any 4 consecutive 

tests exceeds the characteristic tensile splitting strength by 0.3 N/mm² 

ii) 

iii) 

The tensile splitting strength obtained from any individual test is not 

less than the characteristic tensile splitting strength less 0.3 N/mm² 

The characteristic tensile splitting strength is not less than 3.9 N/mm². 

d) The failed specimens shall be checked to ensure the random distribution and 

alignment of the steel fibres to the satisfaction of the Project Manager. Should 

the fibre alignment or distribution be noticeably non-random so as to improve 

the results from the testing above, the tests shall be repeated. 

Durability Test 

Concrete shall be tested for durability properties at a nominal age of 28 days. 

Workmanship 

a) Furnish segments to be mechanically connected across joint faces. Provide 

joint connection assemblies to facilitate structural performance, achieve and 

maintain maximum joint closure and required gasket compression, and 

assist in ring stabilization and ring circularity. 

b) Provide gasket grooves as on designer approved drawings. Design joint to 

prevent lipping, which forms outside of edge of gasket groove, from contact 

with opposing lip during erection and thrusting of adjoining ring to prevent 

damage and spalling. Joint surface upon or against which gasket may bear 

shall be smooth, free of spalling, fractures and imperfections that would 

adversely affect performance of joint. Each segment shall include no less 

than one grout/lifting hole, with lifting insert and non-return valves. 

Identification of Segments 

a) Provide a positive means of identifying each segment that is accepted by 

the Project Manager. Segment identification should indicate the following 

information: 

i) Internal diameter of lining 

ii) Concrete specification 

iii) Segment type designation 


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PT608.6 

PT608.7 

iv) Manufacturer’s name or initials 

v) Date of manufacture 

vi) Mould number 

b) Markings such as logos, trademarks and proprietary information, except 

panel identification markings, are prohibited on surfaces of tunnel liner 

segments. 

Surface Finishes 

a) Ensure that the maximum local irregularity on formed surfaces does not 

exceed rounded protrusion of 1mm. above the general concrete surface. 

b) If the extrados surface is not formed, it shall be finished with a steel trowel 

such that the maximum local irregularity does not exceed a rounded 

protrusion 3mm above the general concrete surface. 

Formwork and Finishing 

a) Conform to the dimensions and tolerances indicated, ensure segments of 

Fabricate steel and concrete moulds with machined steel mating surfaces to 

common design and cast in different moulds are interchangeable. Joints are 

to be watertight and form surfaces shall be prepared to provide segments 

with finished surfaces free from irregularities. 

b) Provide moulds of special sizes and cross sections with metal thickness, 

reinforcement, stiffness and surface finish as required to form concrete 

surfaces smooth, free from irregularities and conforming to the required 

dimensions. 

c) Construct moulds for precast segment with smooth casting faces such that 

a true, sound concrete surface is formed. 

d) Segments of common dimensions and cast in different moulds shall be 

interchangeable. 

e) Provide moulds with individual identifications to ensure that all segments 

cast are marked and fully traceable. 

f) Form mould joint surfaces to provide flat planes at the orientations shown in 

the Works Information. 

g) Make all inserts to mould bolt pockets, holes, grout holes, etc. of approved 

steel or material having a coefficient of thermal expansion similar to that of 

concrete. 

h) Provide steel templates, gauges, and testing apparatus, as required to 

enable the measurement of tolerances to ensure that each segment falls 

within two concentric volumes in space represented as the maximum and 

minimum dimensions allowed. Keep suitably protected from damage and 

distortion, free from dirt and corrosion and ready for use in checking the 

segments as described hereinafter. 

i) Clean and coat mould with non-staining release agent before each reuse. 

j) Securely anchor mould inserts and embedded items to formwork. 

k) Check each mould prior to each production pour to ensure tolerances of 

each form are being maintained. Each mould shall be rechecked after every 

production pour to ensure that no changes occurred in the form during 

casting (under vibration). 

l) Keep a record of all the units cast in each form. Any mould that becomes 

distorted or which casts faulty units shall be withdrawn from service until it is 

proved to the satisfaction of the Project Manager to be corrected. 

m) Formed surfaces – Smooth form finish. 


Page 9 of 13



n) Back face – Segment shall be finished by a steel trowel. Provide a finish 

smooth and free from blemishes to ensure an adequate seal is achieved 

with the tail skin seal of tunnelling machine. 

PT609 

PT609.1 

PT609.2 

SEGMENT CASTING 

Segment Casting Preparation 

a) The maximum variation in the position of the reinforcing bars shall be 

+5mm. Except for internally at joint connectors, grout holes, and as 

otherwise shown, the minimum concrete cover over the reinforcement shall 

be 35mm. Cages shall be sufficiently rigid to prevent deformation during the 

manufacturing process. 

b) Reinforcement cages shall be kept clean and dry and stored in such a 

manner that no distortion occurs. 

c) Clean reinforcement of loose rust, mill scale, and other foreign material. 

d) Fix concrete spacers so that the reinforcement is held firmly in the correct 

position within the formwork with all the cover specified. The spacers shall 

be rigidly fixed to the reinforcement to prevent displacement. If the spacers 

are wired on, the ends of the wires shall be turned into the unit. 

e) Do not use spacers in the circumferential or radial joint regions. The joint 

regions are the areas up to a distance of 100mm from the joint surface. 

f) Furnish concrete spacers made from the approved concrete mix for the 

segments, compacted and cured to the same standard as the segments, or 

from concrete of an equal or higher strength to that identified in this Section. 

Plastic spacers are not to be used. 

g) Saturate all spacers with clean water prior to use. Spacers shall not be 

allowed to dry out after being fixed to reinforcement cages before the 

concrete is cast. 

h) Check reinforcement cages and other embedments within each mould. 

Segment Casting 

a) Produce segments under enclosed plant controlled conditions with 

production areas protected against wind, rain, snow, dust and direct 

sunlight. 

b) The initial concrete placement temperature shall be less than 25°C and shall 

be no less than10°C. 

c) Protect all concrete from hot and cold weather at all times during production. 

d) Consolidate and work concrete into complete contact with forms and 

embedded items. Consolidate and work concrete into complete contact with 

forms and embedded items. Consolidate concrete adjacent to side forms 

and along the entire length of forms to ensure a smooth surface finish after 

stripping of formwork. 

e) Check the first segment cast in any form to confirm that the segment 

conforms to the required dimensions and tolerances. Thereafter as a 

minimum, two percent of the segments cast on each shift, not less than one 

segment per shift, shall be checked on a rotating form/mould basis to 

ensure that the dimensions and tolerances of the segments are maintained. 

f) All units of the same type shall be interchangeable and the dimensions for 

each unit shown in the Works Information shall be accurately reproduced 

within the tolerances indicated in the Works Information. 

g) If an out-of-tolerance segment is found, do not use that segment in the work 

or any other segments from the form found to be out-of-tolerance. 


Page 10 of 13



PT609.3 

PT610 

PT610.1 

PT611 

h) Verify that the segments have attained the design strength prior to shipping 

by comparison with strength gain-maturity curves. Verify results with cube 

test from concrete cured with the segments. 

i) The segments shall be delivered to the tunnel excavation sites in 

undamaged condition. 

Curing 

Segments shall be cured in accordance with the provisions of Eurocode 2 

a) If proposing heat curing, immediately after segments have been cast, place 

the forms in a sealed, vapour-tight enclosure or chamber large enough to 

allow complete circulation of heat 

b) Do not attempt to remove segments from forms until compressive strength 

as required by the design of the segments, as determined by test cubes. 

c) When specified strength is attained, allow segments to cool slowly, do not 

exceed rate of temperature change specified in this Section. 

d) Segments shall be moist cured for a minimum of five days after 

manufacture. The moist curing shall be achieved by placing the segments in 

a special area where water shall be continuously sprayed or atomized, after 

the steam curing to ensure a 100% relative humidity environment. 

e) Protect the segments from thermal shock. Utilize thermal blankets to 

minimize thermal shock. Do not allow rate of change of temperature to 

exceed 18°C per hour. 

f) The curing cycle shall follow the recommendations of AC1517.2R. The 

segments shall be examined immediately after striking for evidence of 

cracking. Cracks greater than 0.15mm shall be treated as a nonconformance. 

SITE QUALITY CONTROL 

Acceptance Tests 

a) Source Quality Control – Factory Tests 

i) Allow the Project Manager access to work areas, equipment for 

performing the inspections. 

ii) Provide equipment including master working templates, gauges and 

callipers adequate to determine accuracies and tolerances in 

manufacture. 

b) Production Test Cubes 

i) Prepare three cubes and cure as specified for each work shift or for 

every 100 mtrs³ of concrete used, whichever is more frequent. 

ii) 

TOLERANCES 

Test cubes for compressive strength as follows: one cube after 7 days 

and the remaining 2 cubes after 28 days. 

Dimensional Tolerances of segments 

Dimensions of individual precast concrete segments shall be within the following 

tolerances:- 

a) circumferential length: ±1mm 

b) thickness: ±1.5mm 

c) width: ±1 mm 

d) bolt holes: size+1mm,-2mm 


Page 11 of 13



e) bolt holes and dowel: positions1mm 

f) sealing gasket grooves: depth ±1mm 

g) sealing gaskets grooves: width ± 0.5mm 

h) longitudinal joints: in a 0.3mm with a rate of deviation plane 

along the axis of the 

not exceeding 0.6mm/m 

tunnel (longitudinal) 

i) In a radial plane: 0.1mm with a rate of deviation 

not exceeding 1mm/m 

j) Circumferential faces: 0.5mm from theoretical plane with 

rate of deviation 

k) Smoothness of other faces: back face:- ±1.5mm 

front face:- ±1mm 

l) mismatch of sealing groove 

at corners: 

>0.5mm 

PT612 

PT612.1 

PT613 

PT613.1 

PT613.2 

PT613.3 

PT613.4 

ADJUSTMENTS AND REPAIR PROCEDURES 

Repair of Segment Defects 

a) Repair or replace structurally damaged and misaligned segments in 

accordance with this Section and to the satisfaction of the Project Manager; 

and to maintain the structural integrity, durability and water tightness of the 

segmental tunnel lining system. 

b) Prior to lining installation, repair minor damage to a concrete segment 

before erection by removing defective damaged area to sound concrete and 

patching with materials and procedures accepted by the Project Manager. 

c) Damage or irregularities to a concrete segment, which may impair structural 

integrity or performance, shall be cause for rejection of the segment by the 


d) The Project Manager shall have the right to inspect, check and reject a 

finished segment not found to be in accordance with the Works Information. 

To measure and determine accuracy of manufacture, the Contractor shall 

provide and make available at all times master templates and working 

templates, gauges, callipers and other equipment as may be required by the 

Project Manager to inspect the segments. 

PRODUCT DELIVERY, STORAGE, AND HANDLING 

Transportation 

Transport, store, and handle units to avoid damage and prevent excessive 

stresses from developing within segments. Follow all instructions from 

manufacturer of precast concrete segmental tunnel lining regarding 

transportation, storage, and handling of segments. 

Segment Support 

Use supports for storing and handling segments to avoid damage; do not subject 

segments to undue strains. 

Prevent damage to segment surfaces during handling and storage. Keep wire 

ropes, chains and hooks from direct contact with segment surfaces, joint 

assemblies, gaskets and joint compression packings. 

Do not store segments with joint compression packing and/or gaskets out-ofdoors 

more than 30 days, unless the gaskets and packers are protected from 

sunlight and weather. 


Page 12 of 13



PT613.5 

PT613.6 

PT613.7 

PT613.8 

PT613.9 

PT614 

PT614.1 

During cold weather, prevent water from filling the pockets and recesses of the 

segments and freezing. 

Ensure segments have attained the specified 28-day design strength prior to 

shipment. Segments to be loaded and shipped shall be a minimum 14 days old. 

Unless otherwise agreed with the Project Manager 

Inspect the segments, remove defective or damaged segments, and repair any 

minor damage, in accordance with specified procedures prior to loading 

segments. 

Arrange deliveries to the site from either the plant or stockpile. 

Polymer Repair Mortar Products: 

a) Deliver materials to the site in original packages or containers bearing the 

manufacturer’s labels and identification. 

b) Store and handle materials to prevent inclusion of foreign matter and water 

deteriorating effects of hot and cold temperatures as prescribed by the 

manufacturer of the materials to prevent inclusion of foreign matter and 

water and deteriorating effects of hot and cold temperatures as prescribed 

by the manufacturer of the materials. 

c) Any material stored past the expiration date shall be disposed of properly. 


Contractor Qualifications 

For the manufacture of the segments employ a qualified firm regularly engaged 

in the manufacture of high precision precast concrete units of similar dimensions 

and tolerances to those specified, and who has provided precision precast 

concrete units to the quality as specified in this Section and shall demonstrate at 

least 5 years experience in manufacture and distribution of high precision 

segments. 


Page 13 of 13

080731 6LYG A1 Particular Tunnelling Specification ... - SCATnow

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