持续降雨对土质边坡稳定性影响研究

通过室内试验、数值模拟并结合工程实例，研究了持续降雨对土质边坡稳定性的影响。结果表明:降雨会在土质边坡表层形成一层暂态饱和区，暂态饱和区的范围会随着降雨历时和强度的增大而逐渐增大；在Geostudio 2012数值模拟中，表现为均质土坡在表层出现的湿润峰随着降雨历时和降雨强度的增大而向坡体深部扩展，在相同条件下，湿润峰在坡体平缓部位扩展深度大，而在坡体陡峭处扩展深度小，导致湿润峰将坡体划分为上部暂态饱和区与下部非饱和区两部分。相同原状土体的黏聚力与内摩擦角随着含水率的增大和减小而相应增大和减小，致使湿润峰上部暂态饱和区土体物理力学性质发生改变，最终导致边坡稳定性系数随降雨的变化而发生变化。因此，在工程建设中出现均质土坡时，必须考虑天然降雨对边坡稳定性的影响，并做好截水及排水设计。

Study on Influence of Continuous Rainfall on Soil Slope Stability

Through laboratory experiments, numerical simulation, and combined with engineering examples, the influence of continuous rainfall on soil slope stability was studied. The result shows that, because of rainfall, there on the surface of soil slope forms a layer of transient saturated zone which will expand gradually with the duration and intensity of rainfall; in the numerical simulation by Geostudio 2012, it manifests that the wetting front occurring on the surface of homogeneous soil slope extends to the deep part of the slope with the rainfall duration and intensity, and under the same conditions, the extension depth of wetting front is large in the gentle part of the slope, but small in the steep part, leading to the slope is divided into two parts by the wetting front:upper transient saturated zone and lower unsaturated zone. It is found that, the cohesion and internal friction angle of the same undisturbed soil increase and decrease with the increase and decrease of water content, which makes a difference on the physical and mechanical properties of the soil in the upper transient saturated zone, and then on the slope stability coefficient. Therefore, in case of homogeneous soil slope in engineering construction, it is necessary to consider the influence of natural rainfall on the slope stability, and to do a good job in water interception and drainage design.