Case Study of Soil Slope Stabilisation Works at Banjo Paterson Park

An existing slope section overlooking Parramatta River in Banjo Paterson Park, Gladesville, NSW experienced a failure in 2017. The existing slope is on the south west side of the park. The unstable slope section is approximately 20 m to 25 m long, 5 m to 8 m height at a grade of approximately 1.5H:1V to 1H:1V.

This paper focuses on the stabilisation option study for the slope remediation and presents a case study of the use of sandstone riverbank wall to retain up to 7.5 m of existing soil slope. Sandstone riverbank wall was selected in preference to soil nail wall or retention system to increase the stability of the existing slope batter, expedited the construction process, reduce the construction cost and complexity, and for landscaping and wall appearance considerations. The detailed design considered both global and internal stability and confirmed adequate factor of safety for each failure mode.

This paper presents the assessment of the slope profile and cause of slip failure, comparison among the proposed stabilisation options, and remedial design undertaken for the selected sandstone riverbank wall. It also provides a discussion on the construction of sandstone riverbank wall.