Real Time Monitoring of a Road Embankment Subject to Coastal Erosion and Slope Instability

In this paper, monitoring the stability of a road embankment at Lawrence Hargrave Drive along the Illawarra coast is discussed. The embankment supports a coastal road and had been subject to an ongoing process of coastal erosion at the embankment toe and instability due to elevated piezometric pressures after heavy or sustained rainfall. In this paper, the stability issues and potential failure mechanisms are discussed. In order to allow a long term solution to be developed, an interim real time, web based monitoring system was installed. An outline of the investigations and geotechnical conditions at the site is presented. The paper discusses the monitoring system, including the instrumentation used (in-place inclinometers, piezometers, rain gauge, wave height buoy and web cam, the development of monitoring plans, the integration of instrumentation to develop a Trigger Action Response Plan (TARP), the development of trigger levels based on antecedent monitoring data, and the successful operation of the system.