Thursday 22nd December 2011

Crossrail tunnelling to start in less than 100 days

The first of eight 1,000 tonne tunnel boring machines that will construct the new Crossrail tunnels has been unveiled.

The 140 metre long, fully assembled tunnel boring machine (TBM) is currently undergoing factory testing. The machine will shortly be dismantled and shipped to London where it will be re-assembled at Westbourne Park ahead of tunnelling commencing from Royal Oak in March.

To construct the 21km of twin-bore tunnel required for Crossrail, eight tunnel boring machines will be required and will undertake ten individual tunnel drives to construct the 6.2m diameter tunnels. At 140 metres, each TBM would just fit just inside the boundaries of a cricket oval.

As the TBMs advance forward, precast concrete segments will be built in rings behind the TBMs. Construction of the concrete segment factory for the western running tunnels between Royal Oak and Farringdon is now complete at Old Oak Common. The plant will begin manufacturing over 70,000 segments for the western tunnels from January.