Lovat TBM Helen has broken through on the $16m Holland Park tunnelling project in London, UK. The 70 tonne machine holed through into the specially designed shaft at Campden Hill Reservoir, completing the 1.2km long, 2.9m i.d. water main tunnel for client Thames Water.
Contractor Murphy & Sons started tunnelling in May 1999. Construction involved tunnelling at depths of 20-50m, with TBM progress reaching up to 25m/day. The tunnel has been lined using pre-cast concrete segments. In total, 10 000 cubic meters of clay weighing 20 000 tonnes were removed during construction.
At present, the water system is run through 12 mains pipes underneath Holland Park Avenue. Because of the high number of bursts in recent years, the tunnel has been constructed to house two new replacement water mains in an attempt to minimise leakage. Installation of the new pipes and surface works is expected to be completed by December 2000.
Dave Allen, Thames Water’s project manager, said: "The tunnelling has avoided a great deal of disturbance at surface level. Work has gone according to plan, and we would like to thank the local community for helping things go smoothly."
The Lovat TBM was previously used to excavate part of the Thames Water Ring Main.
