UK contractor J Murphy & Sons has achieved the first tunnel breakthrough on National Grid‘s 20km long London Connection project. The Lovat TBM, named Doris, reached the intermediary shaft at Centennial Park in north London in February, having completed the 4km drive from Elstree in under five months.
Construction of the 3m i.d. tunnel is now over 50% complete. Doris will continue on to Canons Corner, while her two siblings Caroline and Helen head north and south respectively from Cricklewood to complete the 20km tunnel. Along most of its route, the tunnel runs directly beneath the A5 arterial road at a depth of around 25m.
When complete, the tunnel, one of the longest to be built in London since the construction of the London Water Ring Main a decade ago, will connect new electricity substations at Elstree, Hertfordshire and St John’s Wood. En route it will pass through five intermediary shafts, which will eventually house ventilation and control equipment.
The Brown & Root designed project will replace and upgrade to 400kV the current network of shallow underground cables that supply the capital’s electricity.
The $US56M tunnel is needed to meet the increasing demand for electricity in and around London. The project is being carried out in phases, scheduled for completion by Spring 2005, the tunnel is designed to accept a second 400kV cable as demand increases well into the future.
Related Files
Map: London Connection project
