Projects

Cumberland River geotechnical works - Great Ocean Road

The Victorian Government has invested $53 million in the Great Ocean Road Resilience Project to safeguard the road against erosion.

Project status:

Underway

Update - August 2020

Regional Roads Victoria has completed a major project to stabilise a 160 metre cliff face at Cumberland River on the Great Ocean Road.

In a Victorian first, we have installed an attenuator, which is a giant steel mesh net designed specifically to catch falling rocks that break away from the cliff face and safely slow their fall to rest behind a concrete wall beside the road. This prevents the rocks from falling onto the road.

Overview

How we installed the attenuator:

Geo-tech crews abseiled down the 160 metre cliff face to remove 5700 tonnes of fragile rock by hand using crowbars, shovels, drills and expanding grout.
The fragile rock was toppled to the ground behind a wall of 34 shipping containers filled with pillows of water to resist the impact of the falling rock.
Crews drilled rock bolts between 4m and 9m long into the rock surface for the netting.
Over 6000sqm of steel netting was attached to the bolts secured to the lower section of the wall.

How larger rocks were removed from the cliff face:

Geo-tech crews harnessed to fixing points above the tree line, at the top of the cliff drilled vertical holes on top of the rocks.
They installed expanding grout or airbag jacks into the holes and waited 24 hours for the rocks to crack.
Once the cracks were large enough, crowbars were used to dislodge the pieces of rock until they fell to the ground behind the container wall. The road was closed to traffic while this occurred.
An even cliff face was created by removing dangerous unstable rocks and ledges.
Regional Roads Victoria’s geotechnical engineers were then able to reassess the cliff face and design a combination of geotechnical treatments, including rock netting to make the cliff face safer for the road users below