The team delivering the central section of the project has started Tideway’s first horizontal tunnelling at the main tunnel drive at Battersea; on the surface, assembly of the TBMs is being pushed forward.
These initial holes that are being dug are called ‘adits’, and are essentially starter tunnels at the bottom of the shaft where the tunnel boring machines (TBMs) will start their journeys east and west under the River Thames. These horizontal excavations are supported by a sprayed concrete lining. The team digs two metres forward (called an advance) and spray the uncovered earth with concrete at very high pressures. So far the team has reached advance 21 on the east adit and advance 8 on the west adit. On the surface, the TBM team has been pushing forward with assembly of the two TBMs as all deliveries of components have been completed without incident, allowing the two leviathans of machines to take their form adjacent the offices.
Attention is now turning to the long term role of the site in support of the drives, with focus on the surface now on the installation of the segment handling gantry crane rails and the extensive conveyor system to handle the massive quantities of spoil transported away from the shield (i.e. the drilling head of the TBM).
The Thames Tideway Tunnel is a major new sewer that will help tackle the problem of overflows from the London’s Victorian sewers (millions of tonnes of raw sewage discharge into the River Thames) and will protect the river from increasing pollution for at least the next 100 years. Ferrovial Agroman is delivering the central section of the tunnel, alongside JV partner Laing O’Rourke.