Transient stability analysis method and sensitivity study of unsaturated soil slopes under consideration of rainfall conditions

The infiltration of rainfall is the key external factor that induces landslides, while the infiltration-induced soil strength decay and volume change are important internal factors for landslides. How to consider the impact of transient changes in unsaturated soil strength and volume on the safety factor during rainfall is a key problem to be solved in the prediction of landslides on unsaturated soil slopes. In this paper, transient stability analysis of unsaturated soil slopes is carried out based on GEO finite element software, and sensitivity analysis of factors affecting the slopes is carried out based on grey-scale correlation analysis. The results of the study show that transient stability analysis of unsaturated soil slopes by GEO is fully feasible. Slope instability is typically characterised by shallow instability damage when considering the strength decay of unsaturated soils due to rainfall infiltration. Sensitivity analysis based on grey-scale correlation shows that the factors affecting the stability coefficient in order of sensitivity are internal friction angle φ > cohesion C' > infiltration coefficient K > rainfall ephemeris H > heaviness γ > rainfall intensity P. © 2021, Saudi Society for Geosciences.