Dame Whina Cooper, City Rail Link’s (CRL) Tunnel Boring Machine (TBM), has started the second leg of its four-stage journey below Auckland streets for the country’s largest transport infrastructure project.
The TBM’s 785-metre-long drive from Karangahape Station to Aotea Station in the heart of Auckland’s midtown is planned to finish early in the new year.
The TBM completed its first leg – 860 metres from CRL’s Mt Eden site to Karangahape – last month.
“We’re very happy to be on the move again for Auckland,” says Francois Dudouit, Project Director for the Link Alliance, which operates the TBM. “Our teams above and below ground have adapted successfully to working in a covid environment and arriving safely for a breakthrough at Aotea is our new goal.”
Tāmaki Makaurau Auckland’s recent five-week-long covid lockdown delayed the TBM’s planned September breakthrough at Karangahape. Tunnelling accelerated when lockdown restrictions eased and its Karangahape arrival was well ahead of its rescheduled time.
The 130-metre-long TBM ‘pushed’ its way 223 metres to the northern end of the Karangahape Station cavern to resume its work – cutting into the earth, removing spoil along a conveyor belt, and lining the tunnel with concrete panels.
Dame Whina Cooper’s resumed mahi (work) from Karangahape coincides with the “retirement” of CRL’s two other hard working “ladies”.
Two road header machines – one named Dame Valerie Adams to honour our world and Olympic athletics champion and the other after New Zealand aviation pioneer Jean Batten – have ended their work excavating Karangahape’s two platform caverns. The job was completed with the last breakthrough from the caverns into the ‘box’ where the Mercury Lane entrance to the station is being built.
“This is a job very well done,” says Francois Dudouit. “Construction like this – building a station 35 metres below ground in a busy city – is something New Zealand has not seen before.”
Karangahape will be the country’s deepest railway station. It stretches below the Karangahape Road ridgeline with entrances at Mercury Lane and Beresford Square.
Together, Jean Batten and Dame Valerie Adams excavated and removed approximately 84,000 tonnes of sandstone.
Temporary support within the platform caverns and connecting cross passages or adits has so far involved the installation of 7,000 rockbolts and spraying 6,000 m3 of shotcrete.
Large machines like roadheaders and TBMs working underground are traditionally named after women of significance.
At Aotea, Dame Whina Cooper will be dismantled underground and returned to Mt Eden in sections, reassembled and then excavate the second rail tunnel in 2022.
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City Rail Link’s Tunnel Boring Machine (TBM), Dame Whina Cooper, broke through into the Aotea Station in central Auckland today, marking the end of its epic underground journey for the project and for the city.
Accelerated work that began at City Rail Link’s (CRL) busy Mt Eden site last month will step up a further gear during the summer holidays.