Waterstopping and Control of Water Ingress
Connaught Tunnel, Crossrail
Principal Contractor: Bachy Soletanche (Phase
Vinci Construction (Phase 2)
Works Commenced: January 2013 (Phase 1)
May 2014 (Phase 2)
Works Completed: February 2013 (Phase 1)
October 2014 (Phase 2)
Appointed by the Client to carry out PU resin injection to 2no. one metre deep concrete invert approach ramps to Connaught Tunnel, which runs under the Royal Docks and City Airport in London. Extensive water ingress had been caused following the removal of sections of the concrete invert.
A trial was carried out to calculate the depths angle and quantity of injection holes and likely consumption of resin. This then enabled a full assessment of the scope of works to be undertaken, which included drilling 16mm diameter injection holes at 400mm centres at an approximate angle of 60 degrees to intersect with the lowest point of the cracked concrete invert.
16mm packers were installed complete with non-return valves and then injected TamPur 100 resin to stop the water flow. Following the successful sealing of the cracks, a ‘locked in’ cementitious chase was installed.
Following the successful construction of the central tunnel section, the Company was re-engaged, this time direct to Vinci for Phase 2 of the works. This included:
- Leak sealing
- Hydrophobic grouting
- Hydro-demolition and mechanical breakout
- Sprayed, hand placed and flowable concrete reinstatement
- Recasting of brickwork arches and shafts
- Stainless steel pinning of brick work