Remediation of Landslide Affected Road Using Geocell Reinforcement

Record-breaking rainfall from February to July 2022 caused widespread damage to multiple road sections within the local government area of Shoalhaven NSW, Australia. With approximately 2059 mm of rainfall in the Kangaroo Valley area alone, which was more than double the rainfall what residents would normally experience, Shoalhaven City Council experienced the wettest year on record. As a direct result of this rainfall, multiple sections along several roads have been severely affected by slope instability resulting in road damage (including 98 landslips affecting 23 roads) restricting local residents from accessing even nearby towns. Accordingly, the local Council sought feasible options that could provide temporary yet safe access to local residents. Among a number of feasible options considered, the proposed use of geocell reinforcement was selected as the preferred short-term remediation option to temporarily restore road use and facilitate safe passage. This paper presents a case study of the performance of a landslide-impacted section of Wattamolla Rd, Woodhill, NSW that was stabilised with geocell reinforcement. Limit equilibrium method and finite element analysis were undertaken to design the temporary access through the landslide affected section of the road. This study showed that geocell can effectively be used as a temporary solution and has feasibility as a permanent solution, where roads are impacted by landslide. Results showed that by confining infill material, geocell minimised axial deformations and lateral spreading and provided a semi-rigid platform that improved the stability of the road embankment.