The UK’s largest Tunnel Boring Machine (TBM) has passed its factory acceptance test and started its journey to the Silvertown Tunnel project in London
The TBM measures 11.91m in diameter, the equivalent of almost three double decker buses, which compares to 7.1m for the TBM used on the Crossrail project and 8.85m for the Thames Tideway scheme. The TBM is also around 82m long and weighs 1,800 tonnes – 1,200 tonnes of which being its enormous shield.
The Silvertown Tunnel project will create a 1.4km twin lane road tunnel running beneath the Thames. It is being delivered by the Riverlinux Construction Joint Venture, comprising BAM Nuttall, Ferrovial Construction and SK Ecoplant, on behalf of Transport for London.
The Silvertown Tunnel TBM will set off from the Silverton launch chamber, which is currently being excavated, before being rotated and relaunched from the Greenwich Peninsula to excavate a second tunnel, completing a total drive of 2,244m.
The ability to turn the TBM around is a key feature of its bespoke design, which also incorporates the need to navigate stiff clay layers and boulders in this part of London.
When finished, the TBM will have excavated nearly 600,000 tonnes of material to form the tunnel.
Reduce congestion and toxic air pollution at the Blackwall Tunnel
Helen Wright, head of the Silvertown Tunnel programme at TfL, said: “This a big moment for the Silvertown Tunnel project, which will reduce congestion and toxic air pollution at the Blackwall Tunnel and allow for more bus routes to cross the river at this location. Everyone working on the project looks forward to this impressive machine starting tunnelling in Spring 2022, so we can remain on course to have this vital new river crossing open in 2025.”
