Following the breakthrough at Waterview, Alice will turn around and do it again.
The giant tunnel boring machine Alice has made great progress in the challenging task of digging two separate motorway tunnels on the Western Ring Route in Auckland.
The project, being completed under contract for the NZ Transport Agency, will extend Auckland’s SH20 from its current northwestern endpoint in Sandringham through to Waterview, where it will link with State Highway 16, the Northwestern Motorway.
Associated with the Waterview Connection tunnelling project is an upgrade of the SH16 causeway, which is being raised and widened, with new interchanges at critical access points along its length to cope with the additional traffic to and from the twin tunnels.
Collectively, the projects are known as the Western Ring Route, and when completed in 2015/16, will help ease congestion between major industrial and residential areas, and provide a direct motorway link to Auckland Airport and routes north and south.
The completion of these major projects in Auckland’s northwest also sees the completion of the long awaited complete motorway network around and through the Auckland district.
During August Alice built over 400m of tunnel, averaging around 12 rings a day. She has achieved 28m (14 lining rings) – her best daily rate yet – on two days.
By late August she had passed the 2km milestone, is now less than 300 m from Waterview and is expected to reach daylight on the northern end of her run in early October. This will make the southbound tunnel longer than the 1.94km Lyttelton Road Tunnel, which has held the record as the longest in New Zealand for the past 50 years.
Tunnel construction manager Iain Simmons says the huge machine’s performance is being aided by the weaker East Coast Bays Formation rock mass she is encountering as she approaches Waterview.
Tunnelling is now on track for a late September or early October breakthrough at Waterview. After breakthrough, Alice will be moved onto a massive cradle which will be turned and then slid with the help of ten hydraulic rams into position for her re-launch south. She will then set off on her 2.4km journey southwards and to completion.
Finishing work on both tunnels will then be undertaken, with traffic expected to be flowing both ways in late 2017.