Construction of the Channel Tunnel Rail Link (CTRL) at Stratford entered a new phase when the cutting section of the first tunnel-boring machine (TBM) was lifted into position at the western end of the Stratford Box, ready to construct one of the scheme’s two longest sections of tunnel.
A large crane capable of lifting up to 1500 tonnes was used by contractor Nishimatsu-Cementation Skanska joint venture, which is responsible for the project to construct twin tunnels each 7.5kms long connecting the Stratford Box to St Pancras station.
The cutting section was lifted in three separate parts, each weighing over 200 tonnes, and will be assembled together with the rest of the machine over the next few weeks ready for launching at the end of this month. The second TBM’s cutting section will arrive in August and when both are fully assembled they will be 120 metres long.
The TBMs from Kawasaki are like moving factories, not only excavating the earth but also constructing the supporting ring structure as well as rail line behind them supplying materials such as ring segments, grout and foam. They are crammed full of sophisticated technology, including an air lock to allow access to the pressurised front cutting section, and will cut through the earth at one and a half metres an hour.
Prior to arriving on site, the TBM was transported by ship from Teesside, where it was built in the Haverton Hill workshop, to Dartford.
The arrival of the first TBM follows the hand over of the western end of the Stratford Box by its contractor Skanska Construction.