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

Lee Tunnel, Contract No. 6LYG/A1
PT – Particular Tunnelling Specification - PT200
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.
Thames Water Utilities Limited August 2008
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