降雨时长对边坡稳定性影响的数值分析
Numerical Analysis of Effect of Rainfall Duration on Slope Stability

通过有限元数值模拟，研究了在相同强度但不同降水持续时间的条件下，边坡流体与土壤之间的耦合关系。通过应用强度折减法，将坡面监测点的位移突变和边坡塑性区域的连续贯通作为边坡失稳的判断标准，从而通过数值方法计算出耦合后的安全系数。通过应用强度折减法，我们可以将坡面监测点的位移变化和边坡塑性区域的连续性作为边坡稳定性的判断标准，从而计算出安全系数。研究发现，对于长时间降雨，安全系数下降最显著的阶段是降雨初期阶段，即降雨时长为0小时至24小时的阶段。之后，安全系数下降率逐渐平缓，并稳定于某一数值。降雨首先使岩质边坡浅层土体达到饱和状态，对浅层土体造成危害，进而降低边坡稳定性。降雨入渗作用下的边坡失稳主要是岩质边坡浅层土体发生滑动。本研究结果为边坡的设计管理以及降雨条件下边坡事故的预测和防治提供了分析依据和参考价值。
Through finite element numerical simulation, the coupling relationship between slope fluid and soil under the condition of the same intensity but different precipitation duration is studied. By applying the strength reduction method, the sudden displacement of the monitoring point on the slope surface and the continuous penetration of the plastic area of the slope are used as the criteria for judging the instability of the slope, and the coupled safety factor is calculated by the numerical method. By applying the strength reduction method, we can use the displacement change of the monitoring point on the slope surface and the continuity of the plastic zone of the slope as the criterion for judging the stability of the slope, so as to calculate the safety factor. The study found that for long-term rainfall, the most significant stage in which the safety factor decreases is the initial stage of rainfall, that is, the stage of rainfall duration from 0 hours to 24 hours. After that, the decrease rate of the safety factor is gradually flattened and stabilized at a certain value. Rainfall first makes the shallow soil of the rocky slope reach a saturated state, causing damage to the shallow soil, and then reducing the stability of the slope. The slope instability under the action of rainfall infiltration is mainly due to the sliding of shallow soil on rocky slopes. The results of this study provide an analysis basis and reference value for the design management of slopes and the prediction and prevention of slope accidents under rainfall conditions.