Analyses of convergence and utilisation of SCL-tunnels during excavation

The platform and pedestrian tunnels for the Crossrail Stations at Whitechapel and Liverpool Street have been constructed using Sprayed Concrete Lining (SCL) techniques 20 m to 30 m below the congested urban streets of London. Most of the tunnels were built in two stages. Firstly an approximately 6.3 m Pilot Tunnel has been excavated, followed by a 10.5 m to 11.5 m Enlargement.

As a common part of SCL construction sequence, in-tunnel displacements have been used to monitor stability during construction. This paper provides a comparison between the measured and the predicted displacements in order to provide a feedback to the designer on design assumptions.