From the magazine, Installation, Microtunnelling, Pipe jacking, Water

Freeway microtunnelling

One of Australia’s busiest roads, the Monash Freeway provides a vital link for motorists between the Melbourne CBD and the south eastern suburbs, where more than half of the city’s workforce is employed. In 2016, the Victorian State Government announced plans to upgrade the freeway as part of the AU$5.5 billion West Gate Tunnel Project project – a public private partnership with Transurban.

Fulton Hogan was awarded the contract to manage the freeway upgrade, which includes the addition of 30 km of extra traffic lanes, the strengthening and widening of associated bridges and upgrades to ramps. Construction started in September 2016 and is expected to be completed sometime in 2018.

As part of the upgrade, Fulton Hogan subcontracted Pezzimenti Trenchless to complete a 900 mm diameter bore crossing below the freeway at Heatherton Road, Doveton. Stretching 108 m, it also required the pipejacking installation of a 700 mm Humes reinforced concrete pipeline underneath the off ramp, median strips, and the inbound and outbound lanes of the Monash.

To complete the project, it utilised a Pezzimenti Laserbore – manufactured laser guided, extraction, microtunnelling machine. It bored through a mixture of sandy clays; as it progressed it also encountered sections of fill along the alignment, which posed a challenge, but this was eventually negotiated.

As the closure of the outbound land was required to excavate the retrieval shaft, the retrieval of the bore head had to be completed during the night to cause less disruption to commuters and road users.

Construction took place during a particularly wet April in Melbourne, which presented significant challenges to the Pezzimenti crew. Approximately 50 m into the drive, the bore and launch pit became inundated with water. Undeterred the team pushed on and was able to complete the construction without incident on 27 April 2017.

This article was featured in the June edition of Trenchless Australasia. To view the magazine on your PC, Mac, tablet, or mobile device, click here.

For more information visit the Pezzimenti Trenchless website.

If you have a project you would like featured in Trenchless Australasia contact Assistant Editor Nick Lovering at nlovering@gs-press.com.au

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