Research on the Influence of Spatial Dimensions on the Stability of Large-Scale Slopes under Heavy Rainfall

Abstract

In engineering practice, slope stability is commonly assessed using a two-dimensional (2D) analysis under the assumption of plane strain conditions. However, when dealing with the complex surface geometries of three-dimensional (3D) slopes, especially under short-term heavy rainfall conditions, relying solely on a 2D cross-sectional analysis may not always yield conservative results compared to 3D slope stability assessments. To investigate the applicability of using 2D cross-sections to represent 3D slopes, this study examines the influence of surface geometries on 3D slope stability. By varying the degree and frequency of surface undulations along a certain longitudinal length of the slope, as well as different variations in slope gradient, the impacts of these factors on the safety factor of 3D slopes under rainfall conditions are analyzed. The findings indicate that for 3D slopes with significant surface undulations and high-frequency variations, the safety factor is generally lower compared to that obtained from the 2D cross-sectional analysis. Furthermore, the variation in slope gradient has a more pronounced effect on the safety factor of 3D slopes compared to surface undulations, particularly when the slope gradients are larger than 50°. Therefore, the influence of spatial dimensions on the stability of slopes can be significant when dealing with complex surface geometries of 3D large-scale slopes. It is highly recommended to conduct both 3D and 2D analyses to ensure the accuracy of the slope stability analysis.