Waterview Connection project reaches halfway point

The tunnel Alice has built is the tenth largest diameter tunnel in the world and the longest road tunnel in New Zealand. Alice is 90m long and weighs 3,100t.

"This is a fantastic achievement," said Brett Gliddon, NZ Transport Agency's highways manager for Auckland. "Our construction partners on the Well-Connected Alliance completed the breakthrough safely and ahead of schedule.

"It is a huge engineering feat for New Zealand, one that is attracting worldwide attention. It demonstrates that with local and international experience and expertise, we can deliver infrastructure to equal the best in the world."

Alice will now be turned around to bore the northbound tunnel. The cutting head and its three trailing gantries will be disconnected and each piece taken one at a time from the completed tunnel and turned.

Tunnelling is expected to resume early next year when all the TBM's parts are in place and reconnected.

The conveyor system that removes excavated material and other services required for the machine's operation will also be turned and will follow Alice as she journeys south. By the completion of the second tunnel, they will extend the length of both tunnels - nearly 5km.

A fourth gantry, which operates independently of Alice to install a culvert on the floor of the tunnel, will be the last to be turned. This culvert will carry the services needed for operation of the tunnels once they have been completed.

The TBM's drive south from Waterview to Owairaka is expected to be completed in about October next year.

Approximately a year of work will then remain to complete the mechanical and electrical fit-out of the tunnels, including completing ventilation buildings at both ends and constructing 16 cross passages to connect the tunnels.

The entire project - which also involves building the surface connections to the existing motorways, 9km of new cycleway, new community amenities such as walkways, playgrounds and skateparks, and planting approximately 150,000 trees and shrubs - is due to be completed in early 2017.

The Waterview Connection is one of five projects to complete the Western Ring Route as an alternative motorway to SH1 through central Auckland and across the Auckland Harbour Bridge.