J. Murphy & Sons was awarded a GBP 10M (USD 16M) contract for partial design, construction and project management of an electricity cable tunnel in September. The 1.3km, 2.44m-diameter bore will run from Brentfield Park to Willesden in northwest London, UK. Preliminary Works began on 10 October and the project will finish in August 2013.

A Lovat TBM will excavate the project. Lining will be largely 2.59 wedge block, with bolted wedge block used in areas of existing infrastructure. A Murphy spokesman said, “One critical element is towards the end of the track in Willesden, where the tunnel will cross 200m of rail track before it reaches the substation. Apart from that this project seems relatively straightforward as London Clay is obviously ideal tunnelling material.”

Murphy will also construct three shafts and 143m of shallow tunnel. The company will handle the installation of ventilation equipment and cable support brackets. Four 132kV phase circuits will be carried through the tunnel.

Murphy tunnelling director Darren Ramsay said, “We are very proud to continue our relationship with UK Power Networks on this contract. We will be utilising our in-house resources and experience to deliver the works, including secant piling for one of the shafts.”