flag tunnelling and underground structures waterproofing solutions

FLAG TUNNELLING AND

IndexA Worldwide market leader p. 3The waterproofing is an essentialcomponent in any underground construction. p. 4The Single Layer System p. 6Flag Active Waterproofing System (F.A.W.S.) p. 6Flag Fail Safe Waterproofing System p 7The Flag Vacuum System p. 7“Tailor Made” Philosophy p. 8UNDERGROUND STRUCTURES WATERPROOFING SOLUTIONS1

FLAG TUNNELLING AND

HistoryA Worldwide market leaderFlag S.p.A., the world leading company for over 40 yearsin manufacturing high tech synthetic membrane in PVCand TPO/FPO for the waterproofing of tunnellingconstruction, underground transport systems and belowground structures.In 2007, FLAG S.p.A. enters into the prestigious GroupSoprema“We are confident of our future and very proud ofour past. The Soprema Group has been around forover 100 years, and we intend to be here for the next100 years”Today the Soprema Group is a Worldwide Leader in manufacturingwaterproofing systems, producing more than 150 million square metersper year. With 16 Production Facilities, 12 Subsidiaries and50 Distributors we cover more than 80 Countries around the World.Flag has been producing synthetic membranesfor underground works since the mid 60’s, whenits materials were used in the construction ofthe first underground railway lines in Milanand Rome and in the first tunnels of theL’Aquila-Teramo motorway.Since then, over 100 million square metres ofFlag waterproof membranes have been appliedall over the World. In the past 40 years Flagonmembranes have been used for the mostprestigious road and underground railwaytunnels and also for the basements andfoundations of some of theWorld’s most celebratedbuildings.Today, Flag is one of the World’s leading manufacturers ofsynthetic membranes for waterproofing major civilengineering works.UNDERGROUND STRUCTURES WATERPROOFING SOLUTIONS3

Waterproofing inspiration…high-performance solutionsThe waterproofing is an essential component inany underground construction.Underground Construction is now expected to conform to a life in excessof 100 Years. This means that the requirements of the products used in theconstruction are very high and the quality and durability of thewaterproofing systems are particularly important.Most below ground applications, whether tunnel orbasement, generally require a system solution to bedesigned on a project by project basis and the costs ofproducing such a system are relatively low in comparisonwith the overall construction costs. The benefits that canbe achieved however are considerable.The waterproofing system designed with membranesconsists of various materials for sealing, draining andprotecting whilst also facilitating inspection and repairpossibilities both during and after construction.The correct laying or “installation” of the products byqualified applicators is essential and regular inspection and QualityAssurance are vital to ensure a fully functional system.Water and moisture penetration are a concernin any structure. The main problem is thatalmost all rock and soil contains water eitherdraining from above (seepage) or penetratingfrom below. In some cases the water may beunder considerable pressure.This water can come from a variety of sources:surface water will penetrate down into theground, whilst broken pipes and sewers are anunexpected source of liquid. The watertable must be taken into accountas should migrating water vapour. Underground streams and lakes oftenrun below or past sites and Perched watertables can be a factor, whethernaturally occurring or manmade.It must be assumed that allbasements or tunnels willcome into contact withwater at some time duringtheir life and therefore will allrequire a waterproofingsystem.Geomembranes are used torestrict liquid migration fromone area to another.They are often used also toline canals and man-madewater ways to prevent waterleakage and also to increase flow rates.PVC and TPO/FPO membranes are today widely used to prevent wateringress into belowground structures including being used as liners fortunnels and waterproofing for basements.4FLAG TUNNELLING AND

When planning any underground structure it is necessary to design to keepthe construction dry, not only for the reliability and functionality of thebuilding but also for safety reasons (specially for underground transportsystem and railway tunnel). It is imperative that water be kept away from the structure and the innerworking area. This can only be achieved by incorporating an appropriatewaterproofing system.The creation of an underground siteshould be undertaken with theappropriate involvement of experiencedwaterproofing companies and detailedengineering planning.Thanks to the vast experience over manyyears Flag has developed some of themost advanced waterproofing systemsfor underground constructionFlag provides a wide range of solutionsdesigned according to the site water conditionand the budget of the investor.These solutions range from the simple SingleLayer System through to very technologicallyadvanced Vacuum System (double layer) whichis unique as it allows impermeability testing tobe carried out not only during construction butalso once completed.The Vacuum System also facilitatesthe localised repair of a damagedarea without the need for costlyexcavation.Flag also supplies Single Layersystems with Compartmentalisationand Injection Systems applied on theconstruction joints or directly on thecompartment.UNDERGROUND STRUCTURES WATERPROOFING SOLUTIONS5

Waterproofing SystemsThe Single Layer SystemThe single layer system is asit’s name suggests, and ismade up of anadjustment or protectivelayer of geotextile andthesubsequentmembrane. This system isdesigned to be simple andin-expensive to install butdoes not incorporate anyprotection to the installedmembrane and has no facilityfor the injection of resinsor grouts for future repair.The system is not dividedinto sections and offersonly basic passiveprotection.CompartmentalizationThis system incorporates the basic requirements of a geotextile andappropriate membrane but also includes waterbars at construction joints.To limit the flow of water in case of leakage, the waterproofing membraneis divided into sections. Waterbars are welded onto the membrane tocompartmentalise the system at the location of the construction jointsbefore the concrete is cast. In this way it is possible to prevent water trackingfrom one compartment to the next.These water stops can also be placed at additional locations if so desired,to reduce the size of the compartments.The membrane is then protected by the installation of an additional protectionmembrane (Flagon PZ) or second geotextile.Flag Active Waterproofing System (F.A.W.S.)To seal the compartments, special re-injectable grouting hoses areinstalled onto the waterbars. These hoses are then used to inject cementto fill voids and later to inject resin if a leak occurs in the compartment.The hoses can be re-used if there are subsequent problem.The advantages of this system are that it allows to the contractor tocontrol the water tightness of the installed waterproofing and to carry outrepairs quickly and easily without the need for costly excavation.6FLAG TUNNELLING AND

Flag Fail Safe Waterproofing SystemAn alternative system to seal the compartmentconsists of injecting the resin throgh injectionvalves that are welded onto the membrane.The valves are not completely welded on themembrane and have some openings whichallow to the resin to flow in the compartmentand therefore seal it.Each compartment should be no larger that100 m 2 and up to 4 injection valves arerequired per compartment.The Flag Vacuum SystemTwo layers of waterproofing membrane are used as a “double-ply”system and the entire area is divided into sections or compartmentalised.Each of these sections or compartments is sealed to form a “pocket” or“envelope” approximately 100 m 2 .The top membrane has small studs on the surface so that once thecompartment is formed there is an air gap maintained between the layers.Once the system is sealed, each compartment has 3 or 4 injection valveswhich facilitate the vacuum.It is possible to test the watertightness of thepocket during construction, by sucking out theair with a suction pump to achieve apre-defined negative pressure for a length oftime. If any defects are found they can bequickly and easily repaired before the installationof the protection and lining.The entire system can be tested and theinjection pipes can then be left in place toenable further testing as work proceeds.Vacuum testTypically 3 or 4 injection pipes are used per compartment andthe hoses should be clearly marked and collected to be locatedin an appropriate position so that once the basement or tunnelis complete the ends of the pipes are hosed within an accessbox to facilitate future testing and repair.The walls or vault and floor sections are partitioned separatelyand the hoses from left, right and floor should be easily identifiable.Should there be any water ingress into any compartment oncethe structure is complete it is possible to identify any leaks asthe water will be forced up the injection pipes.UNDERGROUND STRUCTURES WATERPROOFING SOLUTIONS7

“Tailor Made” PhilosophyIt is then possible to inject a water-reacting resin through the same pipesinto the compartment which will form a gel with the water and completelyreseal the pocket, thus providing a fail-safe system.The advantages of this system are that it allows to the contractor to controlthe water tightness of the installed waterproofing and to carry out repairsquickly and easily without the need for costly excavation.The essential characteristics of a waterproofing membrane forunderground works are for products that are flexible and provideoutstanding physical-chemical performance, are durable and haveexceptional workability and weldability.Given the specific and critical nature of the work to be waterproofed, lifeexpectancy should be measured in decades rather than years.“Tailor Made” PhilosophyFLAGON membranes have been designed, formulated and manufacturedaccording to specific application needs, based on a “tailor-made”philosophy.This approach ensures optimisation of results from every perspective:mechanical resistance, resistance to ageing and micro-organism attack,flexibility, ease of installation and, last but not least, environmentalprotection. The membranes are non toxic and can be formulated to be fireresistant according to general requirements and International Norms.Flag also provides a full range of accessory products including waterstops,protection fleeces and injection hoses.8FLAG TUNNELLING AND