Limit analysis of a soil slope considering saturated-unsaturated seepage

This computing method addresses safety factor with respect to unsaturated slope of downstream homogeneous earth dam. Method to calculate safety factor of unsaturated slope is highly connected with shear strength criteria of unsaturated soil and seepage analysis of unsaturated slope. There is a potential risk for the soil slope of a downstream earth dam to burst along the sliding surface. Most slopes in earth dams are in unsaturated state. This computing method is intended to provide safety factor of a soil slope in saturated-unsaturated seepage. Determining the safety factor of a slope provides information to facilitate the safety assessment of a homogeneous earth dam. This computing method covers a procedure for determining safety factor of unsaturated slope of a downstream earth dam with limit equilibrium method, lower-bound and upper-bound method. This computing method is suitable for unsaturated slope. It is revised on the method to evaluate the safety factor of a saturated soil slope. The contribution of suction to the shear strength of unsaturated soil has been considered. In an example, safety factor of a soil slope is calculated in saturated seepage theory or saturated-unsaturated seepage theory. It is found that the safety factor of a slope considered the saturated-unsaturated seepage in a slope and the suction contribution to shear strength is larger than the one only considers the saturated seepage of a slope.