The extension of the Docklands Light Railway in east London to Woolwich, which had involved twin 1,830m long bores below the river Thames, has been opened two months early.
Last month the £180M (US$267M) link was formally opened between King George V and Woolwich Arsenal stations, and providing south east London with a fast link to London City airport, also served by DLR.
The project was developed under the Private Finance Initiative (PFI) by concessionaire Woolwich Arsenal Rail Enterprises, a JV of Land Securities and the Royal Bank of Scotland. The design and build works were performed by Morgan Est (formerly AMEC, prior to acquisition) and Colas Rail.
Excavation of the 5.3m i.d. tunnel was done over 15 months using a 6.05m diameter Lovat EPBM. Geology along the alignment comprises sands and gravels, and below the river there was fissured, flint-embedded chalk with pressures up to 3.5 bar.
The drives were completed in late 2006 and July 2007, respectively (T&TI, August 2007, p7). In mid-2005 work on the entire £180M (2005 prices; US$340M at 2005 currencies) scheme started and in the second quarter of 2006 tunnelling commenced.
Construction also involved building a box station at Woolwich and also a large intervention shaft and headhouse, 15m wide by 40m deep and sunk next to the river flood wall. It is used for power and communications.
