Waterview’s huge tunnel boring machine (TBM), Alice, has been re-launched and is now making a careful start constructing the second of the 2.4km twin tunnels that will connect Auckland’s Southwestern and Northwestern motorways.
The world’s tenth largest TBM broke into daylight on 29 September, having built the first of the tunnels that are part of the NZ Transport Agency’s Waterview Connection project.
The Transport Agency’s Highway Manager, Brett Gliddon, says the turnaround operation that followed was an extraordinary display of engineering innovation and skill.
“Many TBMs are launched, but only a handful are ever turned to do another underground run.
“What is really extraordinary about turning Alice is the sheer size of the machine and the very constrained space in which the manoeuvre has taken place, sometimes with just millimetres to spare” Mr Gliddon says.
After breaking through the ground at Waterview, the 2,400-tonne, 12-metre long machine with its giant cutter head was pulled onto a massive steel cradle which was then slid sideways and turned to face south, the direction it will travel to build the second (northbound) tunnel.
The same process was then followed for the even larger support gantry that will follow Alice as she disappears underground over the next two weeks.
A second, temporary gantry will also accompany Alice underground to provide just enough support equipment for the TBM to tunnel the first 300 metres of the second tunnel.
Tunnelling will then stop while the temporary gantry is removed and Alice’s other two permanent trailing gantries are retrieved from the first tunnel, turned, and reattached.
Other services that support Alice will also be turned, including the conveyor system that removes excavated spoil and the lifting gantry that installs the concrete culvert – the tunnel within a tunnel – that will carry electronic and electrical services.
Full tunnelling will resume in March, and Alice and her entourage are expected to complete the second tunnel and arrive at Owairaka next October.
Mr Gliddon says the turnaround and re-launch has capped off a year of huge progress to complete the Waterview Connection project. This has included completion of two of the four new ramps that will provide access between the Northwestern Motorway and the tunnels, building the foundations of the motorway in the completed tunnel and construction of the surface motorways either end of the tunnels.
“Next year will be just as big as work continues to complete all tunnelling and excavate the 16 cross passages that will connect the tunnels. We will also build the new community facilities, including skateparks and playgrounds, and begin fitting out the tunnels with the mechanical and electrical services they need to operate.”
A timelapse video showing the turnaround can be viewed at: https://www.youtube.com/watch?v=VA5q8qcXiCk&feature=youtu.be(external link)
The Waterview Connection is one of six related projects either finished or underway to complete the Western Ring Route - one of the Government’s seven Roads of National Significance. The 47 kilometre-long motorway will run between Manukau in the south, the upper end of the Waitemata Harbour, and Albany on the North Shore, and ease pressure on the SH1 motorway through the central city area. It will improve transport connections within Auckland, particularly with the international airport, and with the city’s regional neighbours in Northland and Waikato/Bay of Plenty.
The Waterview Connection project is being delivered by the Well-Connected Alliance which includes the 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.
Waterview Connection's Alice, the tenth largest tunnel boring machine in the world.
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