Seepage Characteristics and Stability Analysis of Bedding Slope Under Rainfall

The soft interlayer and rock structure play a significant role in controlling the deformation of the bedding slope, while previous studies seldom consider the phenomenon of sudden change of local response in these key parts under rainfall conditions, and it is not clear about the mechanism of rainfall infiltration and damage mechanism of such slopes. In this paper, a large red-layered flat-dipping bedding landslide was selected as the research object, and numerical calculations based on the van Genuchten model for saturated-unsaturated flow were performed. The hydrological response and distribution patterns of pore water pressure and water content within the slope during rainfall were studied, stability analysis was performed based on the seepage field results, and the landslide evolution process was simulated and reproduced. The results showed that rainfall infiltration produces local saturated areas and forms stagnant layers on the rock layers in the slope, and the thickness and range gradually extend to the vicinity of the weak interlayer. Moreover, slope stability is affected by rainfall infiltration, and the transient safety factor gradually decreases with rainfall. According to the macroscopic deformation process of the slope model, three stages of instability and failure of rainfall-induced red-layered bedding slopes are generalized: slight uplift stage, strong uplift stage, and sliding-bending failure stage. The results of the study can provide a theoretical basis for the study of seepage, destabilization mechanism and stability evaluation of bedding slopes.