A New Calculation Method for the Soil Slope Safety Factor

Based on the unified strength theory, a new method to calculate the plane soil slope safety factor was derived that considers the effect of intermediate principal stress sigma(2) and at-rest lateral pressure coefficient K-0. Calculation examples from the literature were used to compare the new calculation method and the current slice method; the results showed that both provided good consistency. The new method can provide a reference for slope stability evaluation. The new method was used to calculate the soil slope safety factors for different values of intermediate principal stress parameter b, double shear stress parameters u(tau)', and static lateral pressure coefficient K-0. The results showed that the safety factor u(tau)' increased when b was increased; F-s first increased and then decreased when b was increased; and F-s increased when K-0 was increased. These results show that the intermediate principal stress as well as the stress state and its changes cannot be ignored during soil slope stability analysis. The slope soil characteristics and stress state should be considered to determine the unified strength theoretical parameters and static lateral pressure coefficient, maximize the potential of slope soil strength, and effectively reduce the costs of soil slope engineering.