Effect of structural characteristics on the stability of multi-weak rock slopes considering the spatial variability of geotechnical parameters

The slope of open-pit mines is typically characterized by an interaction structure involving multiple weak layers, with these structural characteristics serving as key factors in determining rock slope stability. Under the influence of random factors such as engineering activities and geological structures, the weak layers of the slope and the intact rock layers undergo relative changes. This interaction leads to a more pronounced spatial variability in the geotechnical parameters that inherently exist. Consequently, twenty generalized models of the rock slope, each with different structural characteristics were established by varying the slope angle, weak layer dip, and slope height. The Latin Hypercube Sampling (LHS) method was employed to efficiently generate parameters random fields. Utilizing mathematics software and FLAC3D, these random fields were assigned to the numerical model via an independent program. The variations in statistical characteristics of both the deformation and safety factor of the slope were obtained through the strength reduction method. The results indicate that, for both bedding and anti-dip slopes with stochastic geotechnical parameters, an increase in the slope angle results in a decrease in the safety factor, albeit to varying degrees. Additionally an increase in slope height leads to a reduction in the safety factor of the bedding slope. Reducing the slope angle is more effective than decreasing the slope height in improving stability. As the angle of the weak layers increases, the mean safety factor of the bedding rock slope decreases, while that of the anti-dip slope increases. The stability of the anti-dip slope is significantly greater than that of the bedding slope. The dip of the weak layer has a pronounced effect on the stability of the bedding slope; as the dip angle increases, the failure mode shifts from slip failure along the weak layer to slip-toppling failure. In contrast, the potential slip surface of the anti-dip slope typically manifests as an arc shape that intersects multiple weak layers. The sensitivity of the safety factor to structural characteristics follows the order of slope angle, weak layer dip, and slope height from most to least significant.