Global stability analysis method of flexible cutting slope protection

Considering that flexible support has perfect waterproof and drainage system, it can reduce the influence of rain on expansive soil, and prevent the crack development. Expansive soil slope was divided into three areas, i.e. fracture zone, unsaturated zone and saturated zone. Using different strength indexes, expansive force influence on slope stability was added. Integral method was used to calculate safety factor. The results show that the safety factor calculated by integral method is 33% higher than that of slices method, and that the safety factor decreases 15% when considering expansion force. The new method can better reflect the effect of the drainage system, the influence of reinforcement, and the high strength characteristics of expansive soil under the condition without water.