Physical model experiments for shallow failure in rainfall-triggered loess slope, Northwest China

Abstract

In order to effectively reduce the impact of rainfall-induced landslides on properties and life, it is important to understand rainfall-caused landslides and their sliding mechanisms. The objective of this paper is to study the effects of different rainfall patterns and different slope structures on the deformation and failure process of shallow loess slopes. To achieve the objective, three categories of indoor physical model experiments of a loess slope with and without a vertical joint were implemented under different rainfall patterns. Three kinds of sensors, including volumetric water content, matric suction, and pore-water pressure sensors, were buried in the model slopes to record the internal changes driving deformation. Analyses of the sensor records and the associated deformational changes, and the experimental results under different conditions show that the matric suction in loess slopes decreased gradually. Loess strength reduced with the continuous increase of volumetric water content. After excess pore-water pressure was generated by the slope deformation and poor drainage of the loess, it decreased the effective stress and the loess strength, which resulted in landslides. In addition, it was observed that the influence of slope structure on stability was greater than that of rainfall patterns. This paper attempts to explain the failure mode and triggering mechanisms of shallow loess landslides induced by rainfall.