Compensation grouting at the Docklands Light Railway Lewisham Extension project

As part of the Docklands Light Railway Lewisham Extension project, the construction of nearly 1.1 km of twin 5.85m diameter running tunnels, passing under the River Thames, was undertaken. The slurry shield method combined with compensation grouting was employed in order to limit surface settlements and to control settlement of the overlying structures. Ground and building movements were carefully monitored and as a result, the compensation grouting technique was successfully implemented. This paper briefly describes the tunnel construction, including the compensation grouting, and the results of the ground movement monitoring.