Alice reaches halfway point

The giant tunnel boring machine known as Alice has reached halfway on the first leg of the underground journey at Auckland’s Waterview Connection project.

The New Zealand Transport Agency’s acting highways manager Steve Mutton says Alice has been making excellent progress since work resumed after a two week maintenance shutdown in May.

The machine is now 32.5 metres below the surface and has journeyed 1.2km. Since tunnelling from Owairaka to Waterview began in November, Alice has averaged around 14m per day, excavating spoil and installing the tunnel’s concrete lining.

This means the first tunnel is on target to be completed by late September, he says.

The machine has installed 600 tunnel lining rings, each weighing 100 tonnes and comprising 10 pre-cast reinforced concrete segments. It has also removed 197,000 cubic metres of spoil.

‘‘Alice has consumed $90,000 in power charges and $55,000 for water. It’s another example of the complexity and size of this project,’’ Mutton says.

After arriving in Waterview the machine will be turned around and relaunched on the southbound journey early next year, creating the northbound tunnel as it goes.

Construction of the two tunnels will be completed at the end of 2015. They will include ventilation fans, communication systems and fire protection. Sixteen cross passages, one every 150m, will connect the twin tunnels.

The entire project is due to open in early 2017.