SLOPE STRENGTHENING WORKS ALONG TOM'S CREEK ROAD

Tom's Creek Road runs perpendicular between Oxley Highway and Innes View Road. It links the properties within Tom's Creek Suburb to the main roads. Intense rainfall occurred in March 2013 that caused a number of landslides along Tom's Creek Road. Interim works was carried out in 2014. However, tension cracks on the road pavement occurred after the interim works were completed. Hence, a permanent solution is required. There are three (3) sites that require slope strengthening measures. The slope comprise of colluvial clays overlying moderate to highly weathered basalt. The combination of steeply dipping soil-basalt interface and intense rainfall events have led to the subsequent landslides. Regional Geotechnical Solutions (RGS) was appointed by Port Macquarie-Hastings Council to provide permanent solutions to stabilize the slope. The conforming design solution was to improve on-site drainage, stabilize the soil batters with a combination of mesh facing and erosion control mat which will be anchored by rock bolts, drilled and grouted into rock stratum behind the embankment.

The contractor proposed Maccaferri Steelgrid HR30 (SG HR30) with an underlying layer of erosion control mat as a surface strengthening and protection material. RGS reviewed and accepted the proposal. The ultimate tensile strength of SG HR30 is 180kN/m. The mesh also provides punching resistance in accordance to UNI 11437:2012. Due to its material stiffness, SG HR30 does not require recesses to be excavated or pre-tensioning of the mesh to activate the product mechanical stiffness, which allows faster installation speed and lower installation cost. The supplied SG HR30 has been coated with GALFAN Class A to enable long lasting performance of the mesh facing. The contractor feedback that SG HR30 is very easy to install and enabled savings to the contractor in terms of cost and time.