C310_3

As part of the £14.8bn Crossrail project, HOCHTIEF, in joint venture, built the Crossrail C310 Thames Tunnel: a 2.6km tunnel from Plumstead to North Woolwich, which passes under the River Thames. Our works also included the construction of two portals at either end of the tunnel and four cross passages.

Key features:

  • Two 2.6km, 6.2m diameter bored tunnels beneath the River Thames
  • 400m long, 20m deep portals at Plumstead and North Woolwich
  • Four cross passages
  • Protection of third party assets
  • Major site enabling works
  • Ground treatment
  • Utility works
  • Woolwich Station box lower level concrete works

We bored the tunnels using two 7.1m diameter slurry Tunnel Boring Machines (TBMs) and our innovative ‘Flying Launch’ system.This pushed the TBMs into the ground using a steel pressure ring, tension bars and hydraulic jacks, which were re-used on each launch. Our system reduced the launch time by 75%, increased safety, and saved 123 tonnes of carbon.

We value engineered the TBM launch and reception pits to use unreinforced panels constructed by the same diaphragm wall rigs that would be used for the portal ground engineering works. Coupled with our temporary steelwork solution, this saved £7.7m.

Our design changes and environmental measures – including recycling surplus groundwater for tunnelling processes – led to an 11% overall reduction in carbon emissions across the project and won us a Green Line Award. Continuous monitoring and mitigation measures, including compensation grouting, reduced the risk of ground movement and ensured the safety of third party assets during tunnelling.

We delivered the tunnel on time and budget and won NCE Tunnelling Project of The Year 2016 ($50m- $500m), Considerate Constructors Silver National Site Award in 2014 and 2015 and a CEEQUAL Outstanding Achievement Award.