Crossrail has changed its restoration and improvement plans for the Connaught Tunnel in the Docklands, east London, to what it says is a safer and easier method.
Engineers originally planned to strengthen the central section of the tunnel by removing the existing steel linings and back filling the entire section with concrete foam. These tunnels would then have been enlarged by boring through the concrete to create tunnels that are large enough for Crossrail trains to pass.
Crossrail will now place cofferdams in the Connaught Passage between the Victoria and Royal Albert Docks, pump out the water and create a dry construction site allowing workers to dig down to the tunnel to undertake the enlargement work through a cut and cover approach.
The cofferdam works which will commence in 2013 have been planned in conjunction with the Royal Docks Management Authority and timed to start after the London Boat Show. Vinci has been contracted to carry out the work.
The Connaught Tunnelwas built in 1878 and was part of the North London Line until 2006. The tunnel will be extensively refurbished as part of works to construct Crossrail’s new Abbey Wood branch.