降雨工况下粗粒土高路堤边坡暂态饱和区时空演变规律模型试验

基于室内模型试验及相似理论，利用含水率测试仪、张力计、土压力盒分别监测长时间大雨、短时间暴雨2种降雨工况下粗粒土高路堤边坡体积含水率、基质吸力、坡前推力变化规律，研究这2种降雨工况下粗粒土高路堤边坡暂态饱和区时空演变规律，揭示暂态饱和区变化影响下粗粒土高路堤边坡失稳机理。结果表明：2种降雨工况下降雨初期，暂态饱和区主要分布在边坡表层，体积含水率逐层上升、基质吸力逐层消散；随降雨不断持续，长时间大雨工况下暂态饱和区主要呈S形分布，暂态饱和区扩展过程中路堤边坡各级坡脚处的体积含水率先上升、基质吸力先消散，坡前推力主要分布在路堤边坡坡脚深处，边坡土体抗剪强度削弱区域首先分布在各级路堤坡脚处并逐渐向边坡内部扩展；短时间暴雨工况下暂态饱和区呈J形分布，暂态饱和区在下路堤坡脚处分布的面积较大，暂态饱和区扩展过程中下路堤边坡下部坡脚附近体积含水率先上升、基质吸力先消散，坡前推力由表层向路堤深处逐渐增大，土体抗剪强度削弱区域主要分布在下路堤边坡坡脚处。

Experiment on Spatial and Temporal Evolution of Transient Saturated Zone of Coarse Soil High Embankment Slope Under Rainfall Condition

Based on the similarity theory and the laboratory model test, moisture testers, tensiometers, and earth pressure cells were used to monitor the distribution of volumetric water content, matric suction and forward thrust under the effect of long time heavy rainfall and short time rainstorm. The spatial and temporal evolution law of transient saturated zone of coarse soil high embankment slope under the conditions of long time heavy rainfall and short time rainstorm was investigated. The damage mechanism of coarse soil high embankment slope at the transit saturated zone was revealed. The results show that, at the beginning of rainfall, transient saturated zone mainly appears on slope surface. Volumetric water content increases layer by layer and matric suction dissipates accordingly. With the rainfall going on, affected by long time heavy rainfall, transient saturated zone mainly presents the form of "S". The volumetric water content at the foot of embankment increases and matric suction dissipates firstly. The forward thrust mainly distributes in the depths of the embankment slope. Meanwhile, the shear strength at the foot of embankment slope is more likely to be weakened, and the trend gradually develops into the deep embankment slope. Affected by short time rainstorm, the transient saturated zone mainly presents the form of "J" and distributes near the lower foot of embankment. The volumetric water content near the lower foot of embankment increases and matric suction dissipates firstly. The forward thrust locates on the surface, and then develop into the deep embankment. The weakened area of soil shear strength is distributed on the slope surface and in the lower foot of embankment slope.