Tunnelling activity for the Crossrail metro project in London, UK, has reached another milestone with the lowering of a 550 tonne tunnel boring machine (TBM) into a 40m deep shaft ahead of the start of tunnelling for the eastern section of the new rail line.
Joint venture contractors Dragados and John Sisk & Son used a 1350 tonne Weldex International crane to lower the TBM into place. The 7.1m diameter TBM, named Elizabeth, was manufactured by Herrenknecht.
This operation is due to be repeated again soon in order to lower the second TBM, named Victoria, into place in the shaft.
Andrew Wolstenholme, Crossrail’s chief executive, said, “This is a significant milestone for Crossrail’s progress in east London. Elizabeth and Victoria will construct Crossrail’s longest tunnel section - 8.3km between Canning Town and Farringdon.”
Elizabeth will start tunnelling later this year, travelling under the River Lea towards Canary Wharf. Work has started to prepare Crossrail’s Canary Wharf station to receive Elizabeth, with workers breaking out the hard concrete at the tunnel eyes to allow for the machines to enter the station next year.
Both tunnelling machines will receive maintenance while in the large station box, before continuing their journeys toward Whitechapel, Liverpool Street and Farringdon.
Construction of the western Crossrail tunnels began in May this year, when two TBMs started tunnelling at Royal Oak in west London. A joint venture comprising BAM Nuttall, Ferrovial Agroman (UK) and Kier Construction is completing this part of the project, planned to link Royal Oak tube station in west London to Farringdon, near the centre, with 6.2km of tunnel.
For the entire project, eight tunnelling machines will construct a total of 21km of twin tunnels under London. Crossrail awarded the east and west tunnelling contracts, worth a total of £1.2 billion (€1.5 billion), at the end of 2010.