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The townships of Wye River and Separation Creek was severely impacted by recent bushfires and floods, which led to slope instability and deficiencies in the existing storm water infrastructure throughout the region. The Stanway Drive Landslip Stabilisation Project was commissioned to rectify a section of residential road way impacted by a recent landslip along both the upper and lower slopes of Stanway Drive in Separation Creek. The remedial works included the reconstruction of 180m of rock beaching retaining walls to both upper and lower slopes, in conjunction, GFRP soil nails and erosion control matting was used to stabilise the embankments. Additional stormwater, kerbing and road pavement upgrades were carried out along Stanway Drive.

Geotech's role

As Principal Contractor, Geotech’s works included soil nailing, rock beaching, erosion protection matting, drainage, kerbing and pavement reconstruction. The critical nature of the rectification works required that construction was to be carried out during the winter. This was not ideal, but with smart construction techniques and rainfall runoff management, works were able to be successfully completed within the required time frames. Rock beaching works to the lower slopes required working in and adjacent to a water course. Strict environmental controls ensured no contamination occurred to the surrounding environment. Once the lower beaching works were completed, the upper beaching works could safely be carried out. Specifically selected large local rock was used for the beaching to both lower and upper slopes. Over 400 GFRP soil nails were installed using custom drilling equipment. Over 1200m2 of erosion control matting was mounted over the soil nails to prevent future movement of the reconstructed embankment.

In order to undertake works during the winter, Geotech re-designed the drainage and kerbing along Stanway Drive. This re-design enabled the critical sections of the drainage system to be installed during the early stages of the works and assist with rainfall runoff management during construction.

Disciplines Covered

• Slope Stabilisation
• Soil Nails
• Erosion Protection Matting
• Rock Beaching
• Roadways (kerb and channel, asphalt)
• Drainage