The tunnel boring machine (TBM) on the Waterview Connection project in Auckland, New Zealand has drilled over a quarter of the way through the scheme’s second motorway tunnel.
TBM Alice is 22m below ground and has excavated more than 630m of the 2.4km-long tunnel.
Tunnelling is on track and the TBM is scheduled to breakthrough at Owairaka later this year, according to New Zealand Transport Agency’s highways manager Brett Gliddon.
Alice, the world’s 10th largest TBM, commenced work on the second tunnel after a complex operation to turn the machine around. The TBM’s cutterhead was turned to excavate the first 250m of the second tunnel and provide room for the rest of the machine and other facilities.
“Worldwide, very few TBMs are turned to complete a second run underground and the project’s extraordinary innovation to achieve this manoeuvre with just millimetres to spare at times is now fully complete. All the support facilities for Alice are in place and fully functioning,” said Gliddon.
Alice broke through at the end of September 2014 after excavating the first of the two three-lane tunnels that are part of New Zealand’s largest road transport project.
The tunnels and interchange will link the Northwestern and Southwestern Motorways to complete the Western Ring Route.
The project is being delivered by the Well-Connected Alliance which includes the New Zealand Transport Agency, Fletcher Construction, McConnell Dowell, Parsons Brinckerhoff, Beca Infrastructure, Tonkin & Taylor and Japanese construction company Obayashi Corporation. Sub-alliance partners are Auckland-based Wilson Tunnelling and Spanish tunnel controls specialists SICE.
The NZ$1.4bn (£655M) project is scheduled for completion in early 2017.