Real-time prediction of rainfall-induced instability in sandy slopes

Landslides occur frequently during or following periods of heavy rainfall. In order to understand the mechanism and conditions leading to these slope failures, a comprehensive testing program consisting of constant shear stress drained triaxial tests and model slope experiments was performed using sandy material obtained from a former landslide site. Results of both element tests and model experiments clearly showed that slope failure is induced due to the development of pore-water pressure in slope. As soil moisture contents within the slope approach critical values, ground deformations are mobilized. Therefore, by properly selecting regions where the soil moisture contents must be monitored, possibly in areas where seepage forces will develop, failure initiation in slopes can be predicted. Based on this, a simple monitoring scheme to predict in real-time the occurrence of failures in critical slopes was proposed.