降雨条件下一维土柱垂直入渗模型试验研究及其渗透系数求解

发布时间：2019-03-12 10:39

【摘要】：为研究降雨条件下一维土柱的入渗规律及求解非饱和土体的渗透系数,开发一套模拟降雨条件下一维土柱垂直入渗模型试验装置,对非饱和重塑黄土土柱做了4组不同降雨强度下的一维垂直入渗试验,得到不同降雨强度下垂直土柱的入渗率时程曲线、浸润峰深度时程曲线及监测点体积含水率的变化规律;提出计算非饱和土体渗透系数的新方法,并结合试验结果,得到试验土样非饱和渗透系数与基质吸力的关系曲线。结果表明:(1)降雨强度对垂直土柱的入渗影响较大,当降雨强度小于土柱最小入渗能力时,入渗率等于降雨强度;当降雨强度大于土柱最小入渗能力时,入渗率时程曲线呈无压入渗、有压入渗和饱和入渗3阶段变化。(2)不同降雨强度下,土柱出现积水点和饱和点的历时不同,降雨强度越大出现积水点和饱和点的时间越短,有压入渗阶段越长。(3)在同一降雨强度下,监测点距土柱上表面越远,其体积含水率时程曲线越密集;而同一监测点,降雨强度越大,其体积含水率时程曲线越稀疏。(4)非饱和重塑黄土渗透系数随基质吸力的增大而减小,且渗透系数的对数与基质吸力呈线性变化。
[Abstract]:In order to study the infiltration law of one-dimensional soil column under rainfall and to solve the permeability coefficient of unsaturated soil, a set of model test equipment for vertical infiltration of one-dimensional soil column under simulated rainfall condition was developed. Four groups of one-dimensional vertical infiltration tests were carried out on unsaturated remolded loess soil columns under different rainfall intensity. The time-history curve of infiltration rate, the time-history curve of depth of infiltration peak and the variation rule of volume moisture content of monitoring point were obtained. A new method for calculating the permeability coefficient of unsaturated soil is put forward, and the relation curve between unsaturated permeability coefficient and matrix suction is obtained by combining the experimental results. The results show that: (1) the rainfall intensity has a great influence on the infiltration of vertical soil column, when the rainfall intensity is less than the minimum infiltration capacity of the soil column, the infiltration rate is equal to the rainfall intensity; When the rainfall intensity is greater than the minimum infiltration capacity of soil column, the time history curve of infiltration rate shows no pressure infiltration, and there are three stages of variation of pressure infiltration and saturation infiltration. (2) under different rainfall intensity, the duration of accumulation point and saturation point of soil column is different. The larger the rainfall intensity, the shorter the time of accumulation point and saturation point, and the longer the pressure infiltration stage is. (3) under the same rainfall intensity, the farther the monitoring point is from the upper surface of the soil column, the more dense the time history curve of volume moisture content is. (4) the permeability coefficient of unsaturated remolded loess decreases with the increase of matrix suction, and the logarithm of permeability coefficient changes linearly with the increase of matrix suction, while the larger the rainfall intensity is, the more sparse the time-history curve of volume moisture content is. (4) the permeability coefficient of unsaturated remolded loess decreases with the increase of matrix suction.
【作者单位】：后勤工程学院军事土木工程系;后勤工程学院岩土力学与地质环境保护重庆市重点实验室;重庆市地质矿产勘查开发局;
【基金】：国家自然科学基金资助项目(51479208,51408603) 重庆市基础与前沿研究一般项目(cstc2013jcyj A00010)~~
【分类号】：TU43

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