Preparations for the start of excavation of a 4.5km long extension to the London Ring Main are underway following the lowering of the Lovat 131 TBM at the Stoke Newington shaft.
Contractor Morgan Est is building the tunnel for client Thames Water to link the Coppermills treatment works to supply the Ring Main. It will do so by linking up the existing mains at Stoke Newington and New River Head.
Geology along the route comprises London Clay and Thanet Sands. The 2.85m i.d. tunnel is to be built with precast bolted segmental lining with a secondary, insitu reinforced concrete layer. The alignment passes below tube lines, rail tunnels a canal tunnel and two major sewers.
The contract was awarded to Amec in January 2007, for commencement on site in the third quarter last year. Amec’s tunnelling business was subsequently transferred with other assets when Morgan Est acquired a major part of the group last year. The job is still earmarked for completion in 2010 (T&TI, February 2007, p6).
The extension, being built using the shield “Cleo”, is part of the client’s “Resilience Project” which will take the Ring Main’s potable water supplies to parts of the city still served by old water mains.
Lovat TBM lowered for London Ring Main drive by Morgan Est
