TBM, SCL milestones for Crossrail 03 Jun 2013
Patrick Reynolds for TunnelTalk
- Crossrail has achieved double milestones with the first TBM hole through at Canary Wharf box station last week and the recent completion of a major sprayed concrete lining (SCL) cavern - among the largest in Europe - at Stepney Green Junction.
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Video of first Crossrail TBM breakthrough
Video and photos by Crossrail
- Also on Contract 305, a second identical Herrenknecht TBM, Victoria, is driving a parallel 6.2m i.d. tunnel towards the station at a depth of 28m, with hole through expected shortly.
- Arriving at Canary Wharf Station marks completion of the first, 1.72km long, leg of the 8.3km total distance to Farringdon Station, which borders the east and west tunnelling packages on the scheme. Elizabeth will now undergo maintenance before being pulled fully through the Canary Wharf box station for relaunch.
- "Many thought it would never happen, it seemed almost unimaginable; but now, with the arrival of this gigantic tunnelling machine in the heart of Canary Wharf, grubby with mud and rubble, we can be in no doubt the project is on its way," said London Mayor Boris Johnson.
- The breakthough is the biggest milestone for the project so far, said Crossrail chief executive, Andrew Wolstenholme. He added that the entire £14.8 billion scheme is now more than a third complete.
First Crossrail TBM breakthrough at Canary Wharf box station
- "We are on track to deliver Europe's biggest construction project on time and on budget," he said. Crossrail is to starting phasing in rail services in 2018.
- Two weeks ago Crossrail also reported completion of the first giant SCL cavern at Stepney Green Junction in east London. Construction of the eastbound cavern was finished ahead of schedule by the Dragados/Sisk JV and work on the westbound chamber is well under way, Crossrail said.
- The caverns will interlock, forming a Y-junction for tunnel spurs to the north east (towards Pudding Mill Lane for the rail route to continue on the surface to Stratford and beyond) and south east (to Canary Wharf, Woolwich and run on the surface to Abbey Wood).
- The eastbound cavern is 50m long x 16.6m high x 13.4m across at its widest point, and called for 7500m3 of excavation in clay and placement of 2500m3 of shotcrete. Primary lining is 200mm-250mm thick shotcrete and the secondary, final lining of approximately 170mm thickness is to be applied in about two years time.
- Major advances in measurement control were key to building such large caverns by SCL in a city. The eastbound cavern is sized to pass the two TBMs, Elizabeth and Victoria, due to arrive later this year after boring from Canary Wharf. After pull through at the cavern, the TBMs will bore to Whitechapel and Liverpool Street stations before terminating at Farringdon.
- The two other TBMs driving under east London are Sophia, which has reached Woolwich box station and will be followed by sister TBM Mary, recently launched at Plumstead. They will be relaunched at Woolwich for northward drives under the River Thames to the North Woolwich portal, near the 135-year-old Connaught Tunnel that is being refurbished and strengthened as part of the Crossrail scheme.
- Tunnelling for Crossrail started in May last year with the launch of two TBMs under west London from the Royal Oak portal, near Paddington. The contractor, a JV of BAM Nuttall, Ferrovial Agroman (UK) and Kier Construction, drove the machines to Tottenham Court Road and Bond Street Stations; they will eventually finish at Farringdon.
- Approximately 12km of running tunnel has been excavated so far by the six TBMs already working on the project. The last two machines are to be launched later this year.
SCL to create Crossrail junction caverns - TunnelTalk, September 2012
Rekindled NATM debate-SCL debate opens - TunnelTalk, August 2012
Crossrail sets up for first drives from the east - TunnelTalk, July 2012
All Crossrail TBMs in the Herrenknecht basket - TunnelTalk, September 2011
Crossrail awards tunnelling contracts - TunnelTalk, December 2010
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