Synopsis
The Connaught Tunnel is a 19th-century brick-lined structure that has been renovated to facilitate the route of the southeast spur of London's Crossrail project from Canary Wharf to Abbey Wood. Modifications include the total replacement of the original, twin, single-track tunnels (lined in brick and cast steel) with a single, twin-track, reinforced concrete box. This was partially built in situ where the alignment passes beneath existing dock walls, and partially in cofferdam where it crosses the dock passage between the two Royal Docks (Albert and Victoria). Inverts in the original tunnels were lowered in places to accommodate the design train envelope and overhead line equipment.
This paper outlines the constraints inherent in an undertaking of this nature, and describes the analytical processes that were adopted to assess the performance of the existing brick structures and the new central concrete box section.