Stability Analysis Approach to Block Toppling in Rock Slopes Under Seismic Loads

Rock slope toppling failure is a typical type of slope disaster. It is crucial for engineering practice to quickly and accurately evaluate the toppling stability of rock slopes under seismic loads. Based on Liu’s pseudo-continuous medium method, the geomechanical model for evaluating the stability of rock slope block toppling subjected to seismic loads, considering non-orthogonal characteristics of the structural planes, is established, and the analytical solution for toppling failure is proposed. The relationship between the normal and shear stresses acting at the block base is discussed, and the formula for determining the location of the failure mode transition point in different cases is deduced. Through programmed analysis, the impact of the seismic load on slope stability and the influence of key parameters on the critical seismic influence coefficient are systematically investigated. The research results indicate that the seismic load has a significant impact on slope stability. With increases in the seismic influence coefficient, or decreases in the angle between the seismic load and the horizontal plane, the supporting force required for slope stability increases, and the transition point from toppling to sliding moves towards the slope toe. It is also shown that, when the seismic influence coefficient reaches the critical value, the slope will slide as a whole without toppling. The value of the critical seismic influence coefficient is positively correlated with the internal friction angle of the block base, and negatively correlated with the direction of the seismic load, the internal friction angle of the block side and the dip angle of the block base. This study provides theoretical support for evaluating the block toppling stability of slopes in seismic-prone areas.