The Influence of Horizontal Variability of Hydraulic Conductivity on Slope Stability under Heavy Rainfall

Due to the natural variability of the soil, hydraulic conductivity has significant spatial variability. In the paper, the variability of the hydraulic conductivity is described by assuming that it follows a lognormal distribution. Based on the improved Green-Ampt (GA) model of rainwater infiltration, the analytical expressions of rainwater infiltration into soil with depth and time under heavy rainfall conditions is obtained. The theoretical derivation of rainfall infiltration is verified by numerical simulation, and is used to quantitatively analyze the effect of horizontal variability of the hydraulic conductivity on slope stability. The results show that the variability of the hydraulic conductivity has a significant impact on rainwater infiltration and slope stability. The smaller the coefficient of variation, the more concentrated is the rainwater infiltration at the beginning of rainfall. Accordingly, the wetting front is more obvious, and the safety factor is smaller. At the same time, the higher coefficient of variation has a negative impact on the cumulative infiltration of rainwater. The larger the coefficient of variation, the lower the cumulative rainwater infiltration. The conclusions reveal the influence of the horizontal variation of hydraulic conductivity on rainwater infiltration, and then the influence on slope stability.