Discrete element-based numerical simulation and failure mechanism analysis of anti-dip rock slopes

Anti-dip rock slopes are common in nature, and it is necessary to investigate their failure mechanism. In this study, a numerical calculation model of anti-dip rock slopes was established using the discrete element method. The failure mechanism of the anti-dip slopes was analyzed from macro- and meso-views, and the flexural toppling failure characteristics and development of the anti-dip slopes failure zone were investigated. The accuracy of the numerical simulation was verified using the model test. Furthermore, the influence of the height-width ratio and the bedding surface bonding strength of the anti-dip rock slope was analyzed by numerical simulation. The results showed that the slope angle and rock bed inclination affect the dip angle of flexural toppling failure and the shape of the failure zone, thereby affecting the slope stability. As the slope angle and rock bed inclination increase, the tendency of flexural toppling becomes more pronounced and the shape of the failure zone becomes steeper. Excessive height-width ratio led to incomplete development, steeper shape, and poorer stability of the failure zone. The slope stability increased when the bonding strength of the joints increased but decreased vice versa. The DEM simulation and model test of the anti-dip rock slope can achieve the expected effect when the height-width ratio is no greater than 3:2. The friction coefficient µ of the joints had the greatest influence on θ₂ and ϕ₁, and the normal-to-shear stiffness ratio k_ns/k_ss had the greatest influence on the slope displacement. These results provide a reference for analyzing the failure mechanism and stability evaluation of anti-dip rock slopes.