Tunnelling breakthrough by extraordinary team

Auckland’s City Rail Link project has edged closer to completion after the 7.15 metre-diameter TBM broke through ground at the city’s Te Waihorotiu Station 42 metres below the city’s CBD.

The underground rail system is New Zealand’s first and is the largest transport infrastructure project ever undertaken by the country. The City Rail Link (CRL) will allow Auckland’s rail network to double in capacity.

The two 1.6 km-long tunnels that have just been completed run between Maungawhau and Te Waihorotiu stations. Thirteen months of tunnel construction are now behind the construction team which completed the tunnelling on time despite huge challenges, CRL chief executive Dr Sean Sweeney revealed.

“Building an underground rail network has never been attempted in New Zealand before,” he explained. “To have achieved what this team of 2000 people have in the face of a global pandemic, multiple lockdowns, restricted COVID-working conditions and multiple other challenges is nothing short of extraordinary.”

The tunnel boring machine (TBM) placed 1067 segment rings, removed 130,000 tonnes of spoil and installed precast concrete panels to line the walls. More than 64,200 cubic metres of concrete was used to build the City Rail Link tunnels, according to CRL.

Link Alliance is delivering the main works (stations and tunnels) and comprises Vinci Construction Grands Projets S.A.S; Downer NZ; Soletanche Bachy International NZ; WSP Opus (NZ); AECOM New Zealand; and Tonkin + Taylor.

About the author

Desi Corbett

Desi is the Editor of Concrete in Australia and at the helm of our magazine for 8 years. She was behind the Institute's weekly news bulletins from 2016-2021 and is now writing our focused news items. Desi has been an engineering news and features journalist/editor across all disciplines since 2013 - part of a 30-year career writing for a wide range of industries.