Shallow Sliding Failure Analysis of Weakly Expansive Soil Slope during Wet-Dry Cycles

Weakly expansive soil slopes are known sites of shallow landslides. In this study, soil samples of a natural slope in Zhenjiang, China, were tested by direct shear test during wet-dry cycles, and shear strength characteristics of weakly expansive soil under different wet-dry cycles were studied. The shallow stability analysis method of weakly expansive soil slopes was proposed for this analysis, which takes into consideration the influence of fissures. More than 60 two-dimensional weakly expansive soil slope stability analyses were performed using the strength reduction limit analysis method. The effects of fissure depths and slope angles on lower and upper limit safety factors and failure surfaces were discussed in detail. The results showed that the lower and upper limit safety factors decreased under different fissure depths and slope angles with the increase in wet-dry cycles. The sliding surfaces of weakly expansive soil slopes were all located at the layer with fully developed fissures.