TBMs ready for London sewerage drives Feb 2012
Thames Water News Release
- Two Herrenknecht TBMs are ready to begin their drives as the tunnelling work to upgrade London's overloaded sewerage system finally gets under way.
Herrenknecht TBM lowered for sewerage works drive
- Thames Water is carrying out £675 million of upgrades to five sewage treatment works as well as the £635 million excavation of the four mile (6.4km) Lee Tunnel as part of the Thames Tideway project.
- Last week a 3m diameter Herrenknecht TBM was lowered into the 20m shaft at Beckton sewage treatment works ready to begin a 750m drive that will allow the transport of final effluent from the new extension to meet up with the existing effluent channel on the east side of the works. Excavation is expected to take two months. Works at Beckton are being carried out by Tamesis – a JV of Laing O'Rourke and IMTECH, with the tunnel shaft excavated by Joseph Gallagher Group.
- Once this tunnel and the extension works are complete Beckton sewage works will be able to treat 60% more sewage and fully treat increased flows during heavy rainfall rather than discharging them into the Thames.
- Meanwhile excavation is about to start on the main 7m diameter Lee Tunnel that will connect the Beckton sewage works to London's largest CSO at Abbey Mills Pumping Station in Stratford. Abbey Mills CSO currently accounts for 40% of the total discharge.
Fig 1. Lee Tunnel and proposed Thames Tunnel alignments
- A spokesman said: "Both TBMs are now in their launch shafts at Beckton. We expect excavations on both tunnels to begin later this month."
- The Lee Tunnel is being bored by a closed-faced slurry TBM manufactured by Herrenknecht. It was lowered into the 70m launch shaft in December last year (2011) and is expected to advance at an average rate of 17m/day with tunnelling expected to be completed in late 2013.
- The work is being carried out by MVB, a joint venture of Morgan Sindall, VINCI Construction and Bachy Soletanche.
- The final phase of the Thames Tideway is the proposed £4.1 billion Thames Tunnel, which will run 15.5 miles (30km) from east to west London connecting the 34 most polluting sewer overflows and transferring them to Abbey Mills Pumping Station and then on to Beckton Sewage Works via the Lee Tunnel.
- The consultation phase for this project ends next week, and the Government has already confirmed it as one of a number of priority infrastructure projects, despite its projected cost now running at double initial estimates.
Lee Tunnel shaft sinking progress - TunnelTalk, October 2011
TBM commissioned to tackle London CSO task - TunnelTalk, May 2011
Super sewer to revitalize River Thames - TunnelTalk, March 2009
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