THE STRENGTHENING OF BRUNEL'S THAMES TUNNEL.

Abstract

Construction of Brunel's tunnel under the River Thames commenced in 1825, and was opened to the public in 1843. After several years in use as a pedestrian tunnel, it was converted for railway operation, reopening for rail traffic in 1869. The tunnel eventually became absorbed into the London Underground network, as part of the East London Line. Following a system-wide risk assessment of its subaqueous structures in the early 1990s, LUL concluded that the tunnel was in need of strengthening. A seven-month closure was proposed for the works to be carried out, starting on 25 March 1995. LUL's originally planned relining scheme required significant modification as a consequence of the late Grade II* listing of the tunnel on 24 March 1995. This paper summarizes the site investigation process and evolution of the relining scheme, together with the execution of the contract works, including tracklaying. Separate ground treatment works above the southern section of tunnel are also briefly described. (A)