动力湿化作用下粗粒土高路堤渗流场时空演化模型试验

为了研究动力湿化作用下渗流水在粗粒土高路堤内的迁移特性，自主研发设计制作一种室内喷洒降雨装置及车辆动力荷载模拟装置，开展动力湿化作用下粗粒土高路堤渗流场时空演化模型试验，从时间和空间2个角度描述渗流水在路堤内的迁移特性，然后根据模型试验结果，建立粗粒土渗流场时空演化机制，揭示动力湿化作用下的粗粒土高路堤边坡渐变失稳发育机理。研究结果表明：基于相似理论，开展粗粒土高路堤渗流场时空演化模型试验可以较为真实地反映粗粒土高路堤在动力湿化作用下渗流水的迁移特性；动力湿化作用下，湿润锋首先在路堤边坡表面形成，并逐渐从边坡表面向内部拓展，在坡顶处的拓展速率较小，坡脚处的拓展速率较大；受湿润锋演变规律的影响，路堤边坡监测点负孔隙水压力逐渐减小，体积含水率逐渐增大，坡前应力逐渐增加，位于坡脚浅层区域的应力增加速度较快；依据渗流水的迁移规律，将渗流影响范围内的土体自上而下分为浅层暂态饱和区、渗流水填充区及渗流水湿润区；在动力湿化作用下，粗粒土高路堤边坡将逐渐产生沿坡脚深层滑移的渐变趋势。

Time and Space Evolution Model of Seepage Field of High Embankment with Coarse-grained Soil Under Combined Action of Dynamic Load and Rainfall

This study aims to examine the migration characteristics of seepage water in coarse-grained soil high embankments under the combined action of rainfall and vehicle dynamic loading. An indoor spray rainfall and vehicle dynamic loading simulation device, designed and manufactured by the authors of this study, were used to carry out seepage flow in coarse-grained soil high embankment field model tests. The migration characteristics of seepage water in the embankment were described from the perspective of time and space. Then, according to the results of the model test, the evolution mechanism of the seepage field in coarse-grained soil in time and space was established, and the mechanism of slope instability, under the action of rainfall and vehicle dynamic loading, was revealed. The results, based on a similar theory, show that the evolutionary model test of the seepage field of coarse-grained soil high embankment in time and space can more realistically reflect the migration characteristics under the combined action of rainfall and dynamic loading. Under these conditions, the wet front is first formed on the embankment slope surface and gradually expands from the slope surface to the inside. Moreover, the expansion rate at the top of the slope is slower, whereas the expansion rate is faster at the foot of the slope. Under the influence of the wetting front evolution law, the negative pore water pressure at the monitoring point of the embankment slope gradually decreases, the volume water content and stress gradually increase, and the stress in the shallow area at the foot of the slope increases rapidly. According to the migration law of seepage water, the soil within the influence range of the seepage is divided into the shallow transient saturation zone, seepage water filling zone, and seepage water wet zone, respectively, from top to bottom. Under the combined effect of rainfall and vehicle dynamic loading, the slope of coarse-grained soil high embankment will gradually slide along the depth of the slope foot.