Failure characteristics of shallow soil slope considering surface runoff and interstitial flow

Abstract

Rainfall-induced shallow landslides are widely concerned for their sudden and group occurrences and serious threat to both lives and property. In this study, a hydraulic model coupling surface runoff and interstitial flow was established to study the failure characteristics of soil slopes under heavy rainfall. Based on the coupling of surface runoff and interstitial flow, we propose a modified failure mode for shallow soil slopes. In this mode, the safety factor of the shallow soil slope is derived, while the shear force acting on the slope from surface runoff is considered, as well as the resistance from the upper and lower edges of the sliding body. Compared with the classical infinite slope failure mode, the safety factor obtained by the method proposed herein is slightly larger. Additionally, the drag effect of runoff contributed positively to slope failure, and the safety factor decreased by approximately 7% while considering the drag force in slope stability analysis. Finally, theoretical analysis is verified by simulation experiments, and the results indicate good agreement between calculated and test values for failure shape and critical runoff depth.