Herrenknecht has been selected to supply the TBM for the UK’s Lower Thames Crossing.
The 16.4m-diameter machine will be the largest ever used in Europe, and the third largest ever used in the world.
The TBM, which will dig two parallel tunnels, will be delivered to site and start work in 2028. The new road east of London is due to open early to mid-2030s.
The 120m-long machine, weighing over 5,000 tonnes, will be delivered to site in segments by sea and carried up the Thames to the Port of Tilbury.
The 4.2km tunnel, being built by the project’s delivery partner, Bouygues Travaux PublicsMurphy Joint Venture, will be the longest road tunnel in the UK.
Herrenknecht’s head of project management, Frédéric Battistoni, said the TBM would be the largest machine ever built at Herrenknecht’s headquarters in Germany and the largest variable density TBM ever.
“It will also be equipped with the largest accessible cutting wheel ever built by Herrenknecht. Incorporating several industry-first innovations, the machine has been designed to adapt to changing ground conditions while enhancing safety, efficiency and logistics during tunnelling operations. The machine will support the excavation of both tunnel drives through a planned U-turn configuration,” he said.
The variable density machine will dig through the water table and varying geologies, such as clay and chalk up to 60m below the Thames. It will be powered by electricity from renewable sources.
A single machine will be used to dig both tunnels to save money and reduce the project’s carbon footprint. The machine will begin tunnelling near the Port of Tilbury in Thurrock in 2028, before being turned around to create the second tunnel.
Didier Jacques, tunnel construction director, Bouygues Travaux Publics Murphy JV, said the companies were proud to be leading the construction of the UK’s longest road tunnel.
“In close collaboration with Herrenknecht, the team will now work on the detailed design development of the tunnel boring machine. Our focus remains steadfast: working at pace to reduce carbon emissions, pioneer innovative solutions and embed safety at every stage of construction,” he said.
National Highways says that despite the Lower Thames Crossing being one of the world’s largest diameter tunnels, it will have one of the smallest carbon footprints, as carbon emissions have been significantly reduced. Innovations such as using low carbon concrete to line the tunnel, and changing the design to build less, will help the Lower Thames Crossing be the first major infrastructure project to be carbon neutral in construction.
