Pukete WWTP Grillage – HCC – Diaphragm wall

Hamilton has one wastewater treatment facility: Pukete Wastewater Treatment Plant. As part of Hamilton City Council’s commitment to improving Hamilton’s liveability through upgrading their assets across the network, have set out to upgrade Pukete WWTP.

Consultants Beca were tasked with designing the upgraded plant, which will provide for the quality, capacity, and security of Hamilton’s wastewater treatment for the next 30 years. 

March Construction were engaged directly by Hamilton City Council to construct an inground lattice structure to improve the ground adjacent to the new inlet facility. This lattice structure was to mitigate the liquefaction risk and provide lateral resistance against soil loads from an adjacent sloped ground during a moderate to large earthquake. 

To form this lattice structure March Construction opted using diaphragm walling techniques over the use of Cutter Soil Mixing, due to the high plasticity content of the soil. Digging 13m deep interlocking 800mm thick panels under bentonite support fluid and then back filling with 10MPa concrete, March were able to deliver a solution that met the stringent demands of the design.