Here are the first signs of the tunnels that will be under Precinct Properties' Commercial Bay downtown development being built by Fletcher Construction.
The tunnels are being built from Britomart Transport Centre, underneath the new downtown development and up Albert Street.
The 3.45km twin-tunnel underground rail link up to 42 metres below the city centre will transform downtown Britomart Transport Centre into a two-way through-station that better connects the Auckland rail network.
The twin cut and cover tunnels constructed along Albert Street between Customs & Wyndham Streets will interface with the Fletcher Construction section of tunnels through Commercial Bay.
Precinct Properties' $681 million development includes a new 39 level commercial office tower and a retail centre where the Downtown Shopping Centre used to be opposite Britomart at the foot of Queen Street.
The development, which encompasses Precinct’s surrounding buildings, will be known as Commercial Bay, as it was first called when established as Auckland’s trading hub in the 1800s.
The tower’s foundations, being built by Fletcher Construction, are being dug concurrently with the beginning of the tunnels.
You can now see signs of where the twin tunnels will appear. Here's how it looks:
Updated 17 October 2017
The cut and cover tunnels are being built by installing retaining walls to retain the soil and stop water from entering the site. Tunnels will be constructed, then the concrete floor, walls and roof will be cast and the completed structures backfilled. When the tunnels reach Mt Eden, they will appear at the surface as ‘dive’ structures (like New Lynn Station).
This video explains the cut and cover construction process.