Crossrail’s tunnelling in southeast London reaches the half-way point
27 August 2013 • Author: Crossrail
A major milestone for Crossrail in southeast London has been reached as one of its tunnelling machines reaches Woolwich and the other prepares to start the drive underneath the River Thames.
The thousand tonne machine Mary, who started her journey from Plumstead in May, has broken through into the station box at Woolwich, marking the half-way point of tunnelling south of the river. During her three month journey, Mary has excavated almost 110,000 tonnes of material and installed 811 concrete rings to line the inside of the tunnel.
She has joined her sister Sophia, who reached the Woolwich box in May and is being prepared to start on the second leg of the journey underneath the Thames to North Woolwich.
Crossrail will provide a significant spur to regeneration in and around Woolwich and Abbey Wood on the southeast section of the route, encouraging investment and development as well as supporting jobs and businesses in the local area.
Passengers in southeast London will benefit from some of Crossrail’s most significant time savings. With Crossrail, the journey from Abbey Wood and Woolwich to Bond Street will be at least 15 minutes quicker and passengers travelling to Heathrow will be able to shave around 40 minutes off their journey.
Gus Scott, Project Manager for Crossrail’s Thames Tunnel, said: “It’s great to know that we’re half way through our tunnelling in southeast London. Mary and Sophia have done a fantastic job so far, between them constructing a mile and a half of brand new tunnels from Plumstead to Woolwich.”
Sophia and Mary are constructing the Thames tunnel, which will run from Plumstead, via Woolwich and underneath the Thames to North Woolwich. They are different to the tunnelling machines being used elsewhere on Crossrail. Known as ‘slurry’ machines, they are specially equipped to deal with the chalk, flint and wet ground conditions in southeast London.
As part of the tunnelling process, the excavated soils are pumped out as liquid slurry to a special site treatment plant at Plumstead. The slurry is separated into sand, gravel, water and chalk. The chalk comes out in ‘cakes’ or slabs of filtered chalk particles.