Components for largest-ever UK TBM arrive at Silvertown16 December 2021
Having passed factory acceptance tests on 2 December at the Herrenknecht works in Schwanau, Germany, parts of the giant TBM that will bore London’s Silvertown Tunnel have started to arrive in London.
The machine will be the largest TBM to work in the UK to date and, with a diameter of 11.91m, is significantly larger than the machines used on HS2 (10.26m), Tideway (8.85m), Crossrail (7.1m) and the Northern Line Extension (6.03m).
Working for Transport for London (TfL), design and build contractor Riverlinx Construction JV (BAM Nuttall, Ferrovial Construction and SK Ecoplant) will operate the machine to excavate Silvertown’s US$1.42bn twin tunnels. The 1.4km-long tubes will each have double lanes and run under the River Thames between Greenwich Peninsula and Silvertown in East London.
Piling for the TBM launch chamber at Silvertown has been completed and its excavation is currently underway in preparation for the machine’s launch in Spring 2022. It will bore from there to the Greenwich Peninsula site where it will be rotated and relaunched to dig the second tube, completing a total drive of 2.244m. Alignment geology will comprise mainly layers of stiff clay and boulders. By the time it has finished, the TBM will have excavated nearly 600,000t of spoil which will be taken away on barges along the river, minimising construction traffic using the roads.
“It gives me and the delivery team an enormous sense of pride to have reached this important milestone for the Silvertown Tunnel project,” said Juan Jose Bregel, Project Director, Riverlinx CJV. “Not only seeing the works really taking shape in preparation for launch at the two main sites at Silvertown and Greenwich but feeling the excitement of what is still to come as the pieces of the TBM arrive to be reassembled and launched in the first quarter of 2022.”
The Silvertown Tunnel project was due to start in 2020 but has been delayed by lockdowns. When completed in 2025, it will be the first new road crossing east of Tower Bridge since the Dartford Crossing was built over 30 years ago. Each tube will have a dedicated lane for buses, coaches and heavy goods vehicles, resulting in significantly more buses crossing the river and therefore a greater provision of public transport. Major regeneration on both sides of the river will include buildings above the tunnel entrances, as well as improved provision for walking and cycling.
Once in operation, the tolled crossing is expected to reduce congestion and associated pollution, as well as improve the reliability and resilience of the nearby Blackwall Tunnel, where incidents close the tunnel on a frequent basis and drivers face daily queues.
TfL awarded Silvertown in November 2019 to the RiverLinx Consortium on a design, build, finance and maintain concession. This included various shareholders plus the firms that will design and construct the tunnel: BAM Nuttall, Ferrovial Agroman and SK of Korea. Wayss and Freytag are also providing tunnelling expertise.