Coupling a slope stability model and a fracture flow model for predicting the timing of typhoon-indiced landslide

Triggering hydrology of landsliding can be different between climatic and geologic regions. In Taiwan, large portion of weathered rock fragments contained in mountainous hillslope soils led to a very high conductivity over near surface, and flows within bedrock fractures can be significantly recharged by typhoon rainfalls, and trigger landslides. A coupled model has therefore been developed to predict the timing of rainfall-induced landslides, by integrating a two-layered (soil and fractured bedrock) flow model and a slope stability model. The model was tested in an experiment site located at Hsiuluan Village, northern Taiwan and performed reasonably well in simulating the timing of landslide initiation for a 2004 landslide event. We suggest the model can be applied to other watersheds with similar environment, assuming that reliable rainfall estimates and soil physics data are available.