CHANNEL TUNNEL Rail Link (CTRL) engineers have resumed tunnelling beneath London Underground's (LUL) Central Line after fears of the work causing a Tube tunnel collapse subsided.
LUL stopped CTRL from taking the second bore for the high speed railway under the Central Line tunnel in Stratford, east London until the exact cause of a ground collapse on the CTRL route just 300m away was known.
A 10m diameter hole opened up above the first bore of Contract 240 of the CTRL on 8 February. Contract 240 involves construction of 4.7km twin bored 8.2m diameter tunnels from Stratford to Barrington Road.
CTRL is investigating the incident but it is thought that the hole opened up after three uncharted wells collapsed due to tunnelling vibrations.
LUL engineers, working with CTRL project manager Rail Link Engineering, carried out additional ground investigation around the Tube tunnel.
But they found nothing to alarm them. 'We found a few wells, but not near the Tube tunnel, ' said an LUL source.
'We weighed up the risks and decided it was better to get on and get the TBM through, ' said the source.
INFOPLUS www. nceplus. co. uk/rail