Rehabilitation of a Victorian Railway Tunnel for Crossrail

The Connaught Tunnel, designed by Sir Alexander Meadows Rendel (son of the founder of the eponymous firm of engineers), is located in London’s historical Docklands to the east of the City and is beneath the navigation channel (hereafter called the “Dock Passage”) between the Royal Victoria and Royal Albert Docks (ref. Figure 1). The rail tunnel was built in 1878 by cut-and-cover methods[1] and is formed of brickwork arches on beds of mass concrete. The longitudinal profile of the tunnel and approach cuttings is shown in Figure 2. The dock passage was deepened during 1933 - 1937[2], to accommodate ships of greater draught. This involved the strengthening of the existing twin brickwork tunnels under the passage with cast steel linings and the removal of brickwork above the tunnels. The passage was also widened to accommodate shipping of 24 m beam which involved the partial removal and replacement of the south dock wall using a combination of sheet piles and a relieving platform, with the works being completed in 1959[3].