Business North November 2021

58 | INFRASTRUCTURE Watercare: Central Interceptor Giant tunnelling machine on the way Karen Phelps “We have plans in place to work under the health and safety standards. We have had to be flexible and adaptive as the situation has changed.” to page 60 W atercare’s Hiwa-i-te-Rangi giant tun- nel boring machine (TBM) has been busy since she was launched in July –on the start of a 14.7-kilometre-long journey under Auckland to construct the $1.2b Central Interceptor wastewater tunnel. The TBM cranked into life just before the national COVID-19 lockdown. Sitting at the bottom of a 40-metre launch shaft, the 5.45 metre diameter cutterhead began turning, ti- tanium blades slicing through the earth. Since then, 64 pipe segments have been installed and the TBM has travelled 102.4 metres. Auckland Mayor Phil Goff gave the start-up order at an official ceremony. Later the site was opened to 2000 members of the public. A special walkway was built over the launch shaft, so visitors could see the TBM far below. Information panels explained how equipment worked, the tunnel route and specifications. BUILDINGSTRENGTHANDRESILIENCE 0800478335 steelandtube.co.nz We’re focusedondeveloping innovative solutions for your project, witha valueaddedandcollaborativeapproach. As a leadingprovider of ReinforcingandCompositeFloorDecking, throughour combinedCFDL /Reinforcing teamweareable toprovidea singlepoint of supply for both solutions. Watercare Central Interceptor executive programme director, Shayne Cunis says the TBM’s name was selected by students who attend schools along the tunnel route. “Hiwa-i-te-Rangi is one of the Matariki stars to which Māori would send their dreams or aspirations for the new year. “Everyone was really excited to see how the scale of the project and to see a giant TBM in real life. “We had so many questions about construc- tion methods and about the engineering. They were particularly interested to hear that the wastewater tunnel is going to cross under- neath the Manukau Harbour.” Residents in older suburbs like Point Chev- alier, Westmere and Grey Lynn particularly appreciated the significance of the new tunnel as for years, heavy rain has overwhelmed the network, creating overflows into streams. Due for completion in 2026, the project is being delivered by Ghella Abergeldie Joint Venture (GA-JV). Project director Francesco Saibene says that over the next four years, Hiwa-i-te-Rangi will travel north underground, crossing the Manukau Harbour and finishing her journey at Tawariki St, Grey Lynn. Lasers will guide the route of the TBM, so that the direction is millimetre-accurate. Soil conditions will influence the progress of the TBM’s progress, which is estimated to be 12- 16 metres per day. Francesco says Covid-19 has thrown up challenges and Watercare and GA-JV are fol- lowing MoH guidelines. He says there are high rates of vaccination (85-95 percent) amongst all Central Intercep- tor staff. “We have plans in place to work under the health and safety standards. We have had to be flexible and adaptive as the situation has changed,” he says. “There will be ongoing effects due to projec- tions that we will be in a situation in Auckland where Covid-19 restrictions will not ease any time soon. “The positive news is that we have the capa- bility to continue despite the challenges. “We just need to assess the best way for- ward with the new Covid protocols as Covid is present this lockdown rather than being eliminated and so the work approach needs to be different.”