Integrating GIS and stress transfer mechanism in mapping rainfall-triggered landslide susceptibility

Abstract

In order to build a region having sustainable development as its goal, the mapping of potential hazardous areas is important. The conventional analytical approach to mapping rainfall-triggered landslide susceptibility is to integrate the factors of safety for every cell against infinite slope failure. The calculation of the factor of safety is commonly assumed to be independent between cells. This paper's objective is to contribute an approach of mapping landslide hazards over a region by considering a stress transfer mechanism. First, an equation is given to estimate the overall magnitude of the unbalanced force released from failed cells. The study proposes three models of the directions and magnitudes of stress transfer. An algorithm is presented to incorporate a stress transfer mechanism into a GIS (Geographical Information Systems)-based landslides susceptibility mapping. The proposed approach is applied in a field case in Nantou, Taiwan. The mapping results reveal that the failed cells propagate under the consideration of a stress transfer mechanism. The propagation is more significant for soils with a strain-softening behavior. The flow-routing models predict that the failed cells propagate rapidly in a descending direction. However, the model extended from the method of slices predicts that the failed cells propagate mildly in all directions. This provides simulation results more comparable to field records.