Somerset Regional Council, Gregors Creek Rd Slips

Durack Civil was recently contracted by Somerset Regional Council to complete the Gregors Creek Road Landslips in the central region of Somerset Regional Council. The project involves the restoration of two land slips, at two adjacent locations, with one slip above the road and one slip below the road, and also involves reconstruction of infrastructure assets which were damaged during the February 2022 flood events.

The scope of works includes all assosiated site works such as site clearing, earthworks, geotechnical pavement, surfacing, landscaping and road furniture works required for the reconstruction of the damaged infrastructure. Provision and management of temporary traffic access for the duration of the work, setting out and survey. Traffic management - Gregors Creek Road is a major thoroughfare and was required to stay open to traffic for the full duration of the project. Durack was permitted to close one lane to work within, and the other lane remained open with single lane reversible flow.

The biggest challenge of working within the closed lane was allowing sufficient room for the 60 tonne slew crane to lift the bags into place. This size crane was required to lift the 4 tonne weight to the required distance down the embankment slope. Durack achieved this by widening the road as much as possible on the northern side, and extending the crane's outriggers past the guardrail on the southern side of the road. There was limited space to widen the road because there was a steep incline on the northern side of the road.

Crane operations - The crane outriggers were extended past the guardrail on the southern side of the road, which resulted in them being located close to the steep batter where the downslope landslip had occurred. Durack engaged Geotechnical Engineering support to ensure that the activity remained safe at all times. Constant monitoring of the outrigger pads was required, and part way through the project it was observed that the southern side was lowering, indicating potential instability. At the direction of the Geotechnical Engineer, Durack constructed concrete pier footings to support the outriggers. This enabled the remaining rock bags to be placed safely.