Tunnel on the move

Tunnel on the move The first section of the Metro Tunnel is now complete – with the first tunnel boring machine, TBM Joan, breaking through to complete the journey from Arden Station to the tunnel’s western entrance in Kensington. Since her launch in August 2019, Joan has travelled 1.2 kilometres and installed 4200 curved concrete segments to create 700 rings lining the walls of the tunnel. The segments, each weighing 4.5 tonnes, are among 56,000 being manufactured at a purpose-built manufacturing plant in Deer Park. The second TBM, Meg, has been travelling on a parallel route to carve out the second tunnel from Arden to Kensington. In the east, at the site of the new Anzac Station on St Kilda Rd, the excavated station box is acting as an assembly site for the project’s final two TBMs, Millie and Alice. Pieces of the tunnelling machines began arriving onsite in November 2019 and over the past few months have been individually lifted by a gantry crane inside the acoustic shed and lowered 20 metres underground, where they are being assembled. TBM Alice’s vibrant green 100-tonne cutterhead, the heaviest piece of a TBM, was installed recently while Millie, with bright yellow cutterhead in place, has been pushed into a launch ring in preparation for tunnelling. The launch ring is a common feature of tunnelling and provides the required pressurised environment and support as the TBMs begin tunnelling through the station box towards South Yarra mid-year.  Once fully assembled, tested and commissioned, the TBMs will act as underground factories with a crew of 10, an operator’s cabin, offices, a kitchen and space for concrete tunnel lining segments. Elsewhere on site, work is continuing to build the Domain Precinct’s new station, with the walls and roof now complete in two sections and construction of station walls in the middle section expected to be completed in March • For more information visit metrotunnel.vic.gov.au