A significant milestone for London’s super sewer has been achieved at the Carnwath Road Riverside site in Fulham with the breakthrough of the West main tunnel connection into the Central section. Works on the connection tunnel started in January.  

The breakthrough of the 75m connection tunnel, which has been constructed to join these two sections, brings all three sections of the new Thames Tideway Tunnel together as one.  

When a change was needed to the arrival into the Carnwath Road shaft by TBM Millicent, the teams came together to deliver a solution. Working alongside the West section Joint Venture of Balfour Beatty, Morgan Sindall, and BAM Nuttall, Tideway determined that the best course would be to turn and bury the TBM and for a connection tunnel to be constructed from the Carnwath Road shaft to the main tunnel.    

The final connection between the sprayed concrete lined tunnel and the segmental tunnel involved the West section team carefully breaking out the precast tunnel segments and forming an enlargement around the segmental interface ring. Prior to the works starting the team carried out a full-scale trial of the connection to ensure that the they could achieve the quality required.  

20 km of the 25-km super sewer have been constructed with secondary lining underway. TBM Selina is tunnelling the final section from Chambers Wharf in Bermondsey to Abbey Mills Pumping Station.    

For archive information please click here and uk/54 for tunnelbuilder archive and visit https://www.tideway.london/. 30/21.