Study On Slope Stability Under Rainfall Conditions

Rainfall mainly affects slope stability through rainfall factor and soil water factor.The main methods to evaluate slope stability are safety factor method and probability method.This paper analyzes the influence of rainfall on pore water pressure and safety factor from two aspects: rainfall factor and soil water factor.Some problems of the two evaluation methods are explored and discussed,and a binary evaluation system is proposed based on the advantages of the two methods.(1)The influences of rainfall factors(rainfall type and rainfall intensity)and soil water factors(Van Genuchten fitting parameters \alpha,n,?r)on pore water pressure and safety factor are analyzed.(2)The calculation accuracy and stability of several typical limit equilibrium methods are compared.The Morgen-Price method is used to analyze the influence of slope ratio and gravity on the safety factor caused by shear strength parameters.(3)Morgen-Price method is used to compare and analyze the influence of rainfall factors(rainfall type and rainfall intensity)and soil,water and soil factors(Van Genuchten fitting parameters ,n,?r)on the safety factor.(4)The influence of variation coefficient and correlation coefficient of shear strength parameters on average safety coefficient,reliability index and instability probability is analyzed.(5)Comparing and analyzing the advantages of taking the change of instability probability as the criterion of slope risk assessment in the process of rainfall.(6)The advantages and disadvantages of the safety factor method and the reliability index-instability probability method are compared.Combining the advantages of the two methods,a binary joint index of the reliability safety factor is proposed to evaluate the slope safety state.