Slope stability analysis of expansive soil under rainfall infiltration

Expansive soil is a kind of special unsaturated soil.With the rainfall infiltrating into expansive soil,both of the suction and shear strength will decrease.Thus it's significant to research the expansive soil slope stability under the rainfall infiltration.This paper takes the expansive soil slope of Hefei Rail Transit Line1 test section as the study object.We use the Geo-Studio software to research the influence of the rainfall intensity,duration,soil cracks and the process of time on the stability of expansive soil slope.Based on this,the orthogonal experiment is used to research the slope stability sensitivity of expansive soil's hydraulic parameters(fitting parameter a,n,m of soil water characteristic curve and saturated hydraulic conductivity Ksat).The results show that a long period of weak rainfall has a greater impact on the expansive soil slope stability.Soil cracks can reduce the stability of the expansive soil slope greatly.The influence of rainfall on the slope stability is continuous.Among the 4 hydraulic parameters which affect the expansive soil slope stability,Ksat is the main factor,and the fitting parameter a and n are unimportant factors.