Sophia, Crossrail’s fifth TBM, has begun her journey from Plumstead to North Woolwich as part of the construction of a tunnel under the River Thames for London’s new rail link.
The 110m long, 7.1m diameter Herrenknecht Slurry TBM is scheduled to drill at an average rate of around 100m a week, whilst installing precast concrete segments. The slurry technique, as opposed to EBP being used elsewhere on Crossrail, is being used to deal with the chalk, flint and wet ground conditions that the TBM will encounter in southeast London. Sophia’s sister machine, Mary, is scheduled to start tunnelling in mid-2013, and will construct a second tunnel alongside the first. The Joint Venture Hochtief/Murhpy is constructing the southeastern tunnels between Plumstead and North Woolwich.
Across the whole Crossrail project, eight TBMs will construct 21km of twin tunnels under London. The Crossrail route will pass through 37 stations and run 118km from Maidenhead and Heathrow in the west, to Shenfield and Abbey Wood in the east.
The first two machines Phyllis and Ada were launched in May and August 2012 and are now tunnelling their way from Royal Oak in west London, via Paddington, Bond Street and Tottenham Court Road, to Farringdon.
The third and fourth machines Elizabeth and Victoria were launched in December at Limmo Peninsula, next to Canning Town and will tunnel beneath the River Lea and through the new station box at Canary Wharf on their way towards central London.