Effect of different antecedent rainfalls and SWCCs on slope stability

A homogeneous slope model is taken as an example to investigate the effect of antecedent rainfall patterns and soil-water characteristic curves (SWCC) on slope stability when the saturated permeability coefficient keeps constant, while other parameters vary. The results indicate that the slope stability is affected by soil-water characteristic curve (SWCC) parameters in varying degrees, and the air entry value a has the maximum influence on the slope stability, while n has relatively small influence. Without considering the major rainfall, when a is small, the antecedent rainfall only causes changes of pore water pressure in the shallow part of the slope and has little influence on the safety factor of the slope. While a is large, the depth influenced by antecedent rainfall increases, the water table even raises, thus the slope stability is influenced more. The effect of the antecedent rainfall patterns with a peak on slope stability is more significant than that of the average rainfall type, and the delayed antecedent rainfall influences the most. If the condition with the main rainfall is considered, the antecedent rainfall type will have little influence on the stability of slope when a is small, while it will cause the difference in distribution of pore water pressureat the beginning of the main rainfall when a is large, which further leads to the difference in the minimum factor safety during the main rainfall. The larger n is, the larger pore water pressure in the slope is influenced, and the smaller the lowest safety factor at the major rainfall stage.