Trevi Group selected for Melbourne freeway project

Crews work on the North East Link road project in Melbourne, Victoria, Australia. (Image: Trevi Group)

Trevi Group is an Italian underground engineering firm. Wagstaff Piling is an Australia-based piling company.

According to Trevi Group, the JV will construct the “Lower Plenty Road Interchange”. It will involve installation of 3km (1.9 mi) of 1,200-mm (4 ft) diaphragm wall up to 40m (131 ft) below ground level.

Four new Soilmec hydromills will be used to excavate around 90,000m³ (3,178,320 cu ft) of soil and rock to build the main box and ramps.

“North East Link is the biggest ever investment in Melbourne’s north east,” said Trevi Group. “A major project with 6.5km (4 mi) tunnels from Watsonia to Bulleen, it will fix the missing link in Melbourne’s freeway network, take 15,000 trucks off local roads a day and reduce travel times by up to 35 minutes.”

The firm said the ‘Lower Plenty’ site has unique ground conditions due to ancient geological events.

“Additional geotechnical investigations and careful planning were carried out, allowing the diaphragm wall panels to be successfully installed,” said Trevi Group.

The road and tunnel build will add 10km (6.2 mi) of freeway, which will connect the Metropolitan Ring Road at Greensborough with the Eastern Freeway at Bulleen, in the metro Melbourne region.

Decades of discussion on expanding the freeway system stalled until 2020 when approval and early works began. In 2021, the tunnelled portion of the roadway was increased from 1.9km to 6.5km (1.2 mi to 4 mi).

Originally expected to cost US$16.5 billion in 2017, the price has since risen to $26.1 billion as of last year.

Tunnel work is expected this year with the project scheduled to finish in 2028.

Use of hydromills on the North East Link project

According to Trevi Group, the project is using four hydromills for narrow trench-cutting.

“No other project in Australia has had four hydromills working in one area,” said Trevi Group. “The logistics to keep all hydromills running is a full-time job for the team. Detailed planning sessions are held daily to effectively manage equipment and resources and adaptability is a skill that our team has that allow them to continually achieve the best outcomes.”

Four Soilmec hydromills work the site. According to Trevi Group, it’s the only construction project in the country using four hydromills on a single scheme. (Image: Trevi Group)