Australian contractor, Transfield Tunnelling has completed excavation of the 1.3km long Perth sewer project in Western Australia. Driving the first EPBM to be used under Perth, a 2.6m diameter Lovat, the contractor brokethrough on the 14 May bringing the project in two weeks ahead of schedule.
The EPBM took just eight months to excavate the tunnel under the suburb of Wembley at depths of up to 18m. The machine was designed to cope with the area’s calcareous and siliceous sands being equiped with a chromium carbide plated cutterhead with backloading ripper teeth and Lovat scraper teeth.
Primary lining consisted of 1m long x 0.1m prefabricated concrete segments leaving a 2.1m i.d.
Transfield entered a successful partnering agreement with client the Water Corporation of Western Australia and design and project manager SMEC Australia.
Western Australia Water Corporation Managing Director Dr Jim Gill said, "The machine worked brilliantly. The challenge the Water Corporation faced was to replace a very deep sewer in densely populated residential area, traditional open trench methods would have meant the closure of roads for extended periods. "
The next phase of the project involves installation of a fibre reinforced plastic liner. Upon completion early next year the new sewer will be linked into two previously constructed replacement sections.
