Tunnelling works for Auckland’s CRL have been completed with the final breakthrough of the tunnel boring machine (TBM) at Te Waihorotiu Station (Aotea) on 14 September.
Over the duration of the project, the TBM bored a total of 3.2 km of tunnels, placed over 2000 segment rings and removed more than 260,000 tonnes of spoil.
The TBM is an earth pressure balance machine, meaning it is able to stabilise the earth it excavates to reduce impact on the surface. It has a 7.15 m diameter, weighs 910 tonnes and is 7.15 meters in length.
Now that the tunnels are completed, crews will begin work fitting them out with everything they will need for use:
• 16 km of rails
• 816 km of signal cables
• 247 km of low voltage cables
• 74 km of cable containment
• 86 km of traction cables
The Dame Whina Cooper is now in the process of being lifted out. Despite being custom built for the CRL project, pieces of the equipment will be returned to Germany where manufacturers Herrenknecht AG will repurpose them for future machines.
The 75 tonne cutter head was removed last week, while the shield is being dismantled into six pieces that will each be crane-lifted above ground for removal.
A large amount of the steel reclaimed from the machine is bound for a local recycling yard so that it can be reused by the community.
When fully operational, it is believed that 54, 000 passengers per hour will utilise CRL stations during peak periods – around double its current capacity.
This marks a massive milestone in establishing the future of Auckland’s transport infrastructure.
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