降雨作用下土石混合体边坡力学参数弱化规律与稳定性分析

土石混合体边坡地质灾害是中国最为常见的地质灾害之一,而降雨是其主要诱发因素,降雨条件下边坡劣化机理研究是防灾减灾领域的重要研究方向.通过分析不同含水率条件下土石混合体力学性质试验数据,建立抗剪强度参数随含水率的演化方程;以此为基础,针对西南地区典型土石混合体边坡,考虑降雨条件下力学参数弱化的影响,采用Geostudio软件开展边坡稳定性分析.结果表明:演化方程能有效反映含水率增大对土石混合体抗剪强度具有显著的弱化效应;降雨强度的增大会显著降低边坡稳定性,降雨持时只是降雨过程中某一时刻值的体现,对边坡稳定性影响不大;降雨量与边坡安全系数呈明显线性负相关.研究成果可为土石混合体边坡地质灾害预测与防治提供技术支撑.

Analysis of Weakening Law of Mechanical Parameters of Soil-rock Mixture and Slope Stability under Rainfall Conditions

The geological hazard of soil-rock mixture slope is one of the most common geological hazards in China and rainfall is the main inducing factor. The study of slope degradation mechanism under rainfall conditions is an important research direction in the field of disaster prevention and mitigation. By analyzing the experimental data of the mechanical properties of soil-rock mixtures under different water content conditions, the evolution equation of shear strength parameters with moisture content is established. A study is implemented that considering the influence of the weakening of mechanical parameters under rainfall conditions for the typical soil-rock mixture slope in Southwest China. The analysis of slope stability is carried out using Geostudio software. The results show that the evolution equation can effectively reflect the weakening effect of the shear strength of the soil-rock mixture caused by the increase of the water content.the increase of the rainfall intensity will significantly reduce the slope stability while the rainfall duration is only a reflection of the value at a certain time in the rainfall process which has a little effect on slope stability. The rainfall and slope safety factor are obviously linear and negatively correlated. The research results can provide a technical support for the prediction and prevention of geological disasters on soil-rock mixed slopes.