Waterview Connection breakthrough23 October 2015
NEW ZEALAND – The TBM broke through on the second drive of Auckland’s Waterview Connection project last month. Billed by contractor McConnell Dowell as one of the largest TBMs ever used in the southern hemisphere, Alice, the 14.4m-diameter Herrenknecht EPBM completed its 2.4km-long journey.
The $1.4bn Waterview Connection is New Zealand's largest ever road project. It includes construction of twin three-lane tunnels - the longest road tunnels in the country - and a giant interchange to connect Auckland's Northwestern and Southwestern Motorways (State Highways 16 and 20).
The Well-Connected Alliance JV, consisting of Fletcher Construction, McConnell Dowell, Parsons Brinckerhoff, Beca Infrastructure, Tonkin & Taylor and Obayashi Corporation, is delivering the project. 'Sub-alliance partners' are Auckland-based Wilson Tunnelling and Spanish tunnel controls specialists SICE. Tunnelling first began in 2013 and the first tunnel was completed in September 2014. Alice was then turned 180 degrees to complete her second drive.
Geology was predominantly sedimentary sandstone with average strengths between 1MPa and 5 MPa. There was a small risk that the tunnel would intersect layers of cemented sandstone of up to 120MPa. However, this did not happen.
"Today's breakthrough is a massive milestone for a project that will transform the way Aucklanders get around their city - a brilliant and remarkable effort and a proud day that needs to be celebrated," said the New Zealand Transport Agency's Highways Manager in Auckland, Brett Gliddon.
"The risks associated with constructing tunnels twice as long as the Auckland Harbour Bridge were always high and the Waterview team rightly needs to be congratulated for its engineering skills and innovation to complete this job safely and on time. That's a fantastic achievement."
Work continues, with sixteen cross passages linking the two tunnels still being constructed, as well as M&E fit out. The Transport Agency plans to open the tunnels and the adjacent Great North Road Interchange in early 2017.