scope:

This guidance document has been produced following a formal investigation (LUSEA Reference 22005663) undertaken after an incident of trains striking a bulge in a non structural secondary tunnel lining between Embankment and Waterloo. The bulge in the lining was caused by grouting works, to seal seepage.

This guidance document will focus on London Underground's (LU) requirements for seepage control in Bridges and Structures (B&S) and Deep Tube Tunnel (DTT) assets.

Grouting processes may be used for other reasons including ground treatment to improve strength, compensation grouting for ground movement due to excavation and construction of new tunnel linings. These processes are not covered by this document although elements of the advice may be relevant.

This guidance is not applicable to grouting wall or floor tiles and other non injection processes.

Purpose 

The purpose of this document is to provide guidance on established good practice solutions that meet the requirements for grouting to control seepage in tunnels and structures