Auckland’s City Rail Link project has chalked up another milestones with the completion of mined tunnelling at Maungawhau Station in Mt Eden last week.
The tunnelling crews successfully completed the final 99.5m mined tunnel section, known as the cavern, adjacent to where the project TBM passed through on its second CRL tunnel drive in 2022.
This marks the end of all tunnelling from Maungawhau Station which has used three types of tunnelling – the Herrenknecht 7.15m diameter EPBM ‘Dame Whina Cooper’, cut-and-cover tunnelling and SCL mined tunnelling.
During the 2.5 years of mined tunnelling, crews excavated approximately 15,000m3 of spoil, used about 10,000m3 of concrete and shotcrete and installed around 250 tonnes of steel and 4,500m2 of waterproofing membrane in creating mined tunnels extending 296m.
Link Alliance is delivering the main CRL works – the stations and tunnels consists of Vinci Construction Grands Projets S.A.S., Downer NZ Ltd, Soletanche Bachy International NZ Limited, WSP Opus (NZ) Limited, AECOM New Zealand Limited and Tonkin + Taylor. Project director Francois Dudouit says the completion of mined tunnelling is a significant achievement.
“These people have been on a long journey, literally and figuratively speaking,” Dudouit says. “The team has faced many technical and environmental challenges and have shown both fortitude and innovation in overcoming those obstacles.
“The completion of this stage of the project is a cause for celebration and a source of great pride,” he added.
The occasion was marked with speeches, awards and flags showcasing the multinational team that has delivered this essential part of the CRL construction.
The CRL is a 3.45km twin-tunnel underground rail link up to 42m below the city centre transforming the downtown Waitematā Station (Britomart) into a two-way through-station that better connects the city’s rail network. The cost of the project is now estimated to be $5.493bn a $1.074bn increase on the previous estimate of $4.419bn, which was approved by the Sponsors in May 2019.
Work is now beginning on the fit-out of the mined tunnels, including electrical works, signalling, ventilation and installation of the rail tracks upon which the new CRL trains will run
Construction of the stations and supporting rail infrastructure now expected to be completed by the Link Alliance by November 2025.