The remaining two TBMs required to construct Crossrail will be manufactured by Herrenknecht AG, Germany. The final two TBMs will dig Crossrail’s Thames Tunnel, C310, in south-east London.
To construct the 21km of twin-bored tunnel required for Crossrail, eight TBMs will be required and will undertake ten individual tunnel drives to construct the 6m diameter rail tunnels. The first two TBMs will launch from Royal Oak in spring 2012.
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Earlier this year, Herrenknecht AG was selected by the major tunnelling contractors to build the first six TBMs for Crossrail.
Construction of the Thames Tunnel is being undertaken by a Joint Venture comprising Hochtief Construction AG and J Murphy & Sons Ltd. Slurry TBMs will be used to construct the 2.6km twin bore Thames Tunnel due to the chalk ground conditions in this part of the capital. The remainder of the tunnels, between Royal Oak, Pudding Mill Lane and Victoria Dock Portal will be constructed using EPBMs which will pass through ground which is predominantly London clay, sand and gravels.
The Slurry TBMs will be launched from Plumstead Portal in late 2012 and will tunnel westwards towards North Woolwich. Construction of Plumstead Portal is now underway with work for North Woolwich Portal commencing in early 2012.
The first two Crossrail TBMs are currently being manufactured. Factory assembly of these TBMs begins in October and will complete during November. The TBMs will then be factory tested before being disassembled in readiness for shipping to London. The first TBM components will begin arriving in the UK at Tilbury Docks in December with the second TBM arriving later in January. The TBM components will be transported to Westbourne Park for re-assembly.
Herrenknecht AG will also deliver two TBMs to Limmo Peninsula for the eastern running tunnels in mid 2012, two machines to Stepney Green and two machines to Plumstead later in 2012.
Andy Mitchell, Crossrail Programme Director said: “Work to manufacture the components for the first two Crossrail tunnel boring machines TBMs will shortly complete allowing the assembly process to begin. The TBMs will be fully assembled and tested at the factory over the next couple of months before being dis-assembled and transported to the UK ahead of tunnelling commencing at Royal Oak in spring 2012. A total of eight TBMs will be constructed for Crossrail with the remaining TBMs delivered to London throughout 2012.”
Concrete segments for the western running tunnels between Royal Oak and Farringdon will be manufactured at Old Oak Common.
Work is now underway to construct the tunnel segment factory on railway land at Old Oak Common and on is track to be completed later this year.
When operational, the facility will contain 216 moulds for the 75,000 concrete segments needed to line Crossrail’s western running tunnels. Approximately 50 people will be employed on-site and it will churn out over 200 segments per day at peak. The factory is being built specifically for the production of Crossrail tunnel segments and once tunnelling is complete, it will be removed.
Crossrail is currently finalising arrangements with the tunnelling contractors regarding the location of the other concrete segment manufacturing sites.