Stability analysis of crack slope considering nonlinearity and water pressure

The soil slopes tend to induce the appearance of tension cracks at the top of slope under various factors, which poses an adverse impact on slope stability. Based on Power-Law nonlinear failure criterion, kinematical approach is adopted in this paper to investigate the effects of underground water and vertical tension cracks on stability of slopes. Notice that the tension cracks tend to propagate vertically, and thus a novel failure mechanism composed by the tension crack and logarithmic spiral shear slide plane is postulated. Theoretically, the worst position of crack propagation makes the stability factor minimal, and the failure surfaces can be obtained under different conditions through optimization. According to the proposed mechanism and nonlinear Mohr-Coulomb strength criterion, the stability factor and safety coefficient of slopes are derived. Subsequently, sensitivity analysis with respect to specific examples is conducted to analyze the influence of tension cracks, nonlinear strength parameters and pore water pressure on the slope stability. The results indicate that slope stability weakens gradually at the presence of tension cracks, and the changing degree is more evident with the increase of the slope angle. Meanwhile, nonlinear parameters have more significant impact on the safety factor with the decreasing value of the slope angle. However, the bigger the slope angle, the greater the height of tension cracks, and therefore the more obvious influence of pore water pressure on slope stability. When the slope angle approaches to be vertical, the height of tension cracks increases sharply. As a matter of fact, the height of tension cracks is highly related to geometrical conditions, strength parameters and water effect, which build a mutual relationship to determine slope stability.