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为研究降雨条件下炭质泥岩-土分层填筑路堤的含水特征,采用室内试验与数值模拟相结合的研究方法,开展人工模拟降雨的路堤物理模型试验,分析雨水入渗时路堤内部含水率的变化特征、暂态饱和区演化过程,并结合数值试验对试验结果进行了验证。研究结果表明:短时降雨对路堤表层土体含水率影响较小,随着降雨的持续,其影响程度增大;受填筑形式的影响,各截面含水率分布曲线呈“S”形或倒“S”形;路堤边坡坡面以下同一深度处土体含水率增大的幅度和速率与其高程呈反比,路堤内部同一高程处土体含水率增大的幅度和速率与其距坡面的距离呈反比;降雨入渗形成的暂态饱和区由坡面向路堤内部整体扩展,其上部扩展速度小于路堤下部,同时在预崩解炭质泥岩中的扩展速度快于土中的速度,当暂态饱和区扩展到一定深度后将引起地下水位的升高;模型试验人眼观察的局限性、填筑过程中水分的迁移及尺寸效应,使得模型试验与数值试验结果之间存在一定差异;路堤特征点、截面含水率变化特征以及暂态饱和区分布形式的研究试验成果,对开展炭质泥岩-土分层填筑路堤在降雨条件下的后续崩解机理及失稳模式研究具有参考意义。
In order to study the water characteristics of embankment filled with carbonaceous mudstone and soil under rainfall conditions, the physical model test of embankment simulated by artificial rainfall was carried out by the combination of indoor test and numerical simulation. The moisture content of embankment during rainfall infiltration , The evolution of transient saturated zone, and the experimental results were verified by numerical experiments. The results show that the short-term rainfall has little effect on the moisture content of the soil in the embankment, and the influence degree of the soil moisture content increases with the continuous rainfall. The distribution of moisture content in each section shows “S” Or inverted “S” shape. The amplitude and rate of increase of soil water content at the same depth below the embankment slope slope is inversely proportional to its elevation. The amplitude and rate of increase of soil moisture content at the same elevation within the embankment are different from the distance The transient saturated zone formed by rainfall infiltration expanded from the slope to the interior of the embankment, and the upper part of the transient saturated zone was smaller than the lower part of the embankment. Meanwhile, the spreading rate in the pre-disintegrated carbonaceous mudstone was faster than that in the soil , When the transient saturated zone expands to a certain depth, it will cause the rise of groundwater level. The limitation of the human eyes in the model test, the migration of water and the size effect in the filling process make sure there is a certain relationship between the model test and the numerical test result Differences in characteristics of embankments, characteristics of cross-section moisture content and the results of research on the distribution of transient saturated regions, the follow-up disintegration mechanism and instability mode of embankments with carbonaceous muddy soil under different rainfall conditions Studies have reference value.