City Rail Link (CRL) has achieved a milestone with the breakthrough from the Albert Street tunnels to CRL tunnels across the Commercial Bay site in Downtown Auckland, New Zealand.
The breakthrough has been a gradual process over the past month, which has required a staged approach to excavation, construction of shotcrete support between piles, and demolition of temporary concrete piles separating the two sites.
The tunnels between the two sites meet under the Customs Street traffic deck, which was built in 2017 to keep traffic moving while the work is carried out underneath.
Mayor Phil Goff said: “With the Albert Street trench excavation complete we are one step closer to delivering Auckland’s first underground rail line.
“The CRL is the most significant infrastructure project in New Zealand. When complete it will carry more than 50,000 passengers during peak hours and completely transform how we move about our city.
“The CRL will not only change the way we travel through Auckland’s central city, it will significantly enhance the efficiency of our entire public transport network, freeing-up our streets from bus congestion and delivering more efficient and frequent train services across the city.”
The Albert Street Trench involved 846,000 work hours to date; installation of 360 piles and 155 steel struts; relocation of 250 services; 50,000m² of backfill; and 10,000m² of tunnel box concrete.
CRL CEO Sean Sweeney said that the nature of the project has made the milestone even more significant.
He said: “It’s fair to say that getting to this point has not been without its challenges. This is the largest transport project ever undertaken in New Zealand and building it within the middle of a built-up city is no small task.”
Sweeney said that the CRLL contractor Connectus, the McConnell Dowell and Downer joint venture team, will now take up construction of the remaining third of the tunnel box and backfilling of the trench will continue until it is covered, by mid-2019.
Early in 2019, the tunnels from the former CPO (Britomart) site will also connect to tunnels across the Commercial Bay site, which will provide a tunnel section from Britomart through to Wyndham St.
Image: City Rail Link tunnel construction in Commercial Bay site in Downtown Auckland, New Zealand, achieves breakthrough. Photo: Courtesy of City Rail Link Ltd.