The installation of the Donvale Branch Sewer in Melbourne’s north-east has reached the halfway mark, with approximately 2,500m of the sewer installed using microtunnelling – eliminating the need for any open-cut trenches on the project.
Pezzimenti Trenchless was contracted to install the branch sewer in the Yarra Valley Water project, with MFJ Constructions, the project’s principal contractor. The complex project includes drilling under major roads, sensitive council reserves with a high number of trees, and private properties.
The most challenging aspect of the installation is the crossing of the Mullum Mullum Creek, which occurs up to six times along the alignment of the pipeline.
Commencing in early 2016, Pezzimenti Trenchless has overcome challenging conditions, allowing for the continued success of the project. The sewer’s location has extremely hard siltstone ground conditions, including veins of quartz and sections where the ground changes from siltstone to clay.
There is also mixed ground conditions along the creek, including an old creek bed with river pebbles and silt. Pezzimenti has also taken into account the limited access along the sensitive council reserves, and has made sure nearby trees were preserved.
The scope of the project covers 4,200m of microtunnelling, with sizes including 427mm GRP Hobas, 550mm GRP Hobas, 650mm GRP Hobas, 718mm GRP Hobas, 752mm FRP Hobas, and 225 PVC.
Pezzimenti has used its extensive microtunnelling experience, combined with solid research and planning, to overcome the complexities of the project and allow it to move forward without delays.