By lyndamyer
As New Zealand’s largest bored water tunnel, Auckland’s Central Interceptor reached another breakthrough by arrival of TBM Hiwa-i-te-Rangi at Havestock Road, marking her fifth breakthrough on the project.
Considering the difficult ground water conditions, this machine broke through into the shaft underwater, as Jerwin Gutierrez, Ghella Abergeldie’s senior associated tunneling engineer, said.
Excavation of the 14.7km pipeline is up to three TBMs that are Hiwa-i-te-Rangi, Domenica and Victoria, and during the latest breakthrough, 9880m of the main tunnel has been excavated.
Storing 226,000m3 of wastewater, controling the flows into treatment plants as well as decreasing the number of wastewater overflows into Auckland’s waterways and the Waitemata Harbour, will be the works of the Central Interceptor.
The project comprises three elements: the main tunnel, Link Sewer B and the CC09 Connector Sewer.
While TBM Domenica has completed its 800m drive on Link Sewer B, it was relaunched in February for the second, and final, 300m drive. Crews are now hand-tunneling a 23m adit from the Link Sewer B tunnel to the main Central Interceptor.
Additionally, TBM Victoria has completed three of the six drives for the CC09 Connector Sewer and advancing a continuous, 10-hour concrete pour at the Western Springs site will be another landmark of this project earlier this year. More than 40 concrete lorries arrived every 15 minutes for 10 hours to complete the base slab of the 30m-deep shaft.
The location of commissioning TBM Dominica twice for Link Sewer B was the Haycock Avenue site in Mt Roskill and a 110 tonne lid has been secured over the 30m-deep shaft.
North of Auckland, work is also under way on Watercare’s 5km Warkworth to Snells Beach wastewater pipeline. In late February TBM Piper was launched on her second drive.
The scheduled date for completion of this project is the current year.
