Sydney Metro TBM, Kathleen, has passed its final inspection and is now ready to launch from Barangaroo next month to dig the historic rail crossing deep under Sydney Harbour.
The 975 tonne Herrenknecht mixed shield slurry TBM was assembled deep under Barangaroo and will soon start digging the first of twin 1km long, 6m i.d. tunnels, 40m below the Harbour at its deepest.
After building the first tunnel, Kathleen will have her cutterhead and main section lifted out at Blues Point and placed on a barge to return to Barangaroo. The machine’s support trailers will be pulled back to Barangaroo inside the first tunnel.
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Kathleen will then build the second tunnel under Sydney Harbour after that, the whole TBM will be retrieved at Blues Point and taken away by barge. The machine is expected to tunnel through clay, silt and sediment under the harbour.
TBM Kathleen will join the four other Herrenknecht TBMs currently digging from Marrickville and Chatswood towards the harbour’s edge. Together, all five TBMs will deliver twin 15.5km rail tunnels for Australia’s biggest public transport project.
Tunnelling contractor, John Holland/CPB/Ghella, which was awarded the $2.81bn contract in June 2017. The schedule sees the tunnelling contract conclude in 2021.