TBM Launch Imminent
Final checks are now underway before the Tunnel Boring Machine (TBM) starts cutting into Auckland soil, excavating the first of the two rail tunnels that will completely change the way people travel around Auckland.
The 130-metre-long Dame Whina Cooper TBM is currently sitting pretty at the Mt Eden station site, with its cutterhead sitting flush against the wall of the 50-metre tunnel portal that was previously dug using diggers/drills.
The official launch will follow a ceremonial launch event on May 7, which will be attended by Transport Minister Michael Wood, Auckland Mayor Phil Goff, Dame Whina Cooper’s whanau, Auckland iwi, City Rail Link and Link Alliance staff.
At this event, the cutterhead will be turned on, signalling the final testing and commissioning phase.
The TBM will be operated by the Link Alliance, the group of New Zealand and international companies responsible for CRL’s main stations, tunnels and rail systems contract.
It will excavate 1.6 kilometres under the central motorway junction and Karangahape Road into central Auckland to connect with the CRL tunnels already built from the Britomart Station.
The TBM has three jobs as its crawls below Auckland: excavating spoil, removing spoil by conveyor belt from the tunnel, and lining the tunnel walls with concrete segments.
TBM FACTS
Each tunnel will be approx. 1.6km long
The tunnels will run between Mt Eden and Aotea Stations, via Karangahape Station
The TBM has been named after a groundbreaking New Zealand woman - Māori rights champion Dame Whina Cooper
TBM tunnelling is due to start in May 2021
The TBM will excavate the two CRL tunnels in two separate drives
Each drive will take about 9 months
The TBM will travel at an average of 15 metres per day, but up to 32 metres a day during peak operation
It will reach depths of up to 42 metres underground
When the first underground drive is completed, the TBM’s front section – the cutterhead and shield – will be dismantled and lifted out of the ground and taken back to Mt Eden. Meanwhile, the TBM’s supporting gantries will be transferred back through the tunnel and across the stations to Mt Eden. All of the TBM’s sections will then be reconnected at Mt Eden for the second drive in 2022
While the TBM is underground, people above it will feel little to no impacts. This is because it is an Earth Pressure Balanced TBM – it controls and balances the pressure of the earth it excavates which stabilises the tunnel face and reduces any possibility of settlement occurring
To operate the TBM, there will be a crew of around 12 people including electricians, mechanics, and drivers
Once underground, the TBM will operate 24 hours a day, 7 days a week