Bouygues Murphy Joint Venture has begun the search for a mega tunnel boring machine (TBM) to deliver the Lower Thames Crossing, which will feature some of the widest road tunnels in the world. The JV plans to use a single TBM to drive both 16.4m diameter northbound and southbound bores, a move aimed at cutting costs without extending the overall programme.
The tunnelling package is advancing as the project’s forecast cost climbs towards £11bn, up from the £9bn figure given earlier this year. Government funding of £3.1bn is expected to be combined with around £7.5bn of private finance to deliver the new crossing.
Construction of the northern tunnel portal is due to start next summer, including a 26m-deep launch chamber for the TBM. The chamber will also accommodate a temporary segment factory to cast the concrete rings that will form the tunnel lining.
The three-lane, 4km-long tunnels will be driven up to 65m below the Thames Estuary, where water pressure could reach 6.5 bar. The TBM will be engineered to safely withstand these pressures as it advances beneath the river.
Tunnelling is scheduled to begin in 2028, starting from the northern side of the crossing. Once complete, the tunnel portals and associated structures will be buried beneath Tilbury Fields, a new landscaped park overlooking the Thames near the docks.
Roads and Buses Minister Simon Lightwood said the launch of the TBM procurement marks a major step forward for the scheme, which received £891m in the Budget. He said the Lower Thames Crossing will unlock capacity across the Thames, ease congestion at Dartford and strengthen connections between ports, manufacturing centres and communities, while acting as a driver of jobs, growth and opportunity.
