14 - 03 - 2013
Article by Claire Symes
Construction of the tunnels on the western section of Crossrail have reached the third way point with both tunnel boring machines (TBM's) having together completed 5km of tunnelling between Royal Oak and Farrington.
The first TBM - Phyllis, which was launched in May last year - is expected to pass close to the edge of western ticket hall, which is currently being excavated by the Costain Skanska joint venture, next week after setting a new weekly profess record of 217m last week.
The second TBM - named Ada - was launched in August last year and is currently under Hyde Park and has around another kilometre of tunnelling to reach Bond Street.
Excavation work on the eastern ticket hall at Hanover Square has been advocated by a joint venture of Bam Nuttall, Ferrovial and Kier (BKF) to its full depth at the western end to allow sprayed concrete lined (SCL) tunnels to be advanced which will interrupt the route of Phyllis and allow for maintenance of the TBM before it continues on towards Farrington.
Ada will pass directly into the eastern ticket hall box, which is formed from 462 secant piles, but the shaft excavated to the tunnel depth will be backfilled with foamed concrete ahead of the TBM's arrival to allow the tunnelling operation to continue uninterrupted.