Ground conditions are a key factor in the ease and success of trenchless operations, though even the toughest conditions can be overcome with the right technology and operator experience. Pezzimenti Trenchless recently put its expertise to the test on a challenging sewerage upgrade project with Yarra Valley Water and MFJ Constructions.

While part of the project was designed for open-cut work by MFJ Constructions, the trenchless component of the project played an important role in completing the upgrade.

For Pezzimenti Trenchless, the scope of work for the Cooper Street Sewer Duplication Project in Somerton, Victoria, included the installation of 700m of DN 650mm GRP pipe through basalt, with grades of one in 400. The most difficult and important bore was 90m underneath the Hume Highway.

“The ground conditions were some of the worst and most challenging we have come across, and we have seen it all,” Pezzimenti Trenchless Director, Joe Pezzimenti, said.

Not only was the location a challenge, but the ground conditions proved to be problematic due to the depth of the new gravity pipeline, which was between three and five metres. While dealing with the interface between clay and basalt, the team encountered boulders and mixed ground conditions.

Over a period of six months, two crews of three members used Pezzimenti-developed equipment, including Pezzimenti cutters, which were suited to handle the tough local conditions. Using reliable, fit-for-purpose technology, and with microtunnelling experience dating back to the 1980s, the company successfully completed the line, which is now fully operational.

“It took all our operators’ experience and expertise to get these bores done on line and on grade,” Mr Pezzimenti said.

The newly installed pipe and 24 new sewer manholes are designed to reliably cater to Melbourne’s growing northern suburbs, and reduce the likelihood of sewage spills during heavy rain.

For more information on how Pezzimenti Trenchless can assist you with your next trenchless project, visit

Lauren ‘LJ’ Butler is the Assistant Editor of Utility magazine and has been part of the team at Monkey Media since 2018.

After completing a Bachelor of Media, Communications and Professional Writing at the University of Wollongong in 2014, and prior to writing about the utility sector, LJ worked as a Journalist and Sub Editor across the horticulture, hardware, power equipment, construction and accommodation industries with publishers such as Glenvale Publications, Multimedia Publishing and Bean Media Group.

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