TBM commissioned to tackle London CSO taskMay 2011
Paula Wallis, TunnelTalk
Thames Water's construction contractor has taken delivery of the Herrenknecht TBM for the Lee sewer tunnel, deep below London. In a handing over-ceremony in Germany last week the Morgan Sindall/Vinci/Bachy Soletanche (MVB) JV accepted the fully assembled and factory tested machine before its dismantling into components for shipping.
Fig 1. Tideway aligment with the Lee Tunnel to the north east
Herrenknecht machine start-up
MVB won the £400 million (US$647 million) design-build contract in January 2010 and will use the closed faced slurry machine to bore the 6.4km (4 mile) tunnel. The Lee is the first of two tunnels in Thames Water's mega £2 billion (US$3.25 billion) Thames Tideway project. It will close down the city's worst combined stormwater overflow facility at Abbey Mills that discharges more than 16 million tonne of sewage a year into the River Lee, a principal Thames River tributary downstream of central London.
The sewer tunnel, the deepest ever in the UK, runs at up to 75m beneath the east London suburbs and requires the sinking of four large diameter shafts; three of up to 25m i.d. - two at Beckton and another at Abbey Mills - and a fourth 80m deep by up to 38m diameter at Beckton to house a massive pumping station to lift flow from the proposed 32km long Thames Tunnel into the treatment works.
The 8.88m diameter machine is being disassembled at Herrenknecht's Schwanau factory for transport by barge to the UK next month, where it will be reassembled for its drive. Tunneling is expected to begin in January 2012, with completion scheduled for late 2013.
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