Comparisons of Safety Factors for Slope in Nonlinear Soils

Slope stability assessment is one of the most important issues for geotechnical engineers. In the framework of a nonlinear failure criterion, four different types of safety factors are presented and their relationships are investigated for soil slope in this study. The variational method is incorporated into the kinematic approach of limit analysis to assess the stability of soil slope with known geometric boundary, and seismic effects are considered. The seismic loads are simplified as external forces acting on the slope. A rotational failure mechanism is used to describe the sliding mode of slopes. The differential equations for the sliding surface and corresponding stress distribution are derived using the variational method and then are employed to generate the sliding surface via the fourth-order Runge-Kutta approach. To avoid the computational complexity, the energy-work balance equation of the kinematic approach, instead of the static equilibrium equation, is used to judge whether the state of the slope is critical. The safety factor is designed as the minimum factor that brings the slope in the limit state. Computational schemes are proposed to calculate the values of safety factors. The validity of the proposed approach is demonstrated through comparison with previous works. Finally, parametric study is conducted to further reveal the relationships among the four types of safety factors.

Automated summary

In this study, the stability assessment of soil slope with known geometric boundary and seismic effects was evaluated using the variational method incorporated into the kinematic approach of limit analysis. A rotational failure mechanism was used to describe the sliding mode of slopes, and computational schemes were proposed to calculate safety factors. The validity of the approach was demonstrated through comparison with previous works, and a parametric study was conducted to further reveal the relationships among the four types of safety factors.