Abstract: In order to study the relationship between landslides and rainfall, the antecedent effective precipitations of different return period were used to analyze the influence of soil moisture on the shear strength parameters of soil body and matrix suction. Then a new method was presented to quantitatively evaluate landslide failure probability under different rainfall return periods based on response surface and simplified Bishop integral method. In additional, the method was applied to in an example and the result showed that a higher failure probability of landslide was calculated with the increase of rainfall return period and rainy days. But considering the probability of rainfall itself, a growing rainfall return period did not mean increase in failure probability of landslide. A slightly stability factor and a lower failure probability of landslide can be calculated based on matrix suction.
