考虑任意初始条件的均质土质覆盖层降雨入渗解析解

发布时间：2018-01-30 21:24

本文关键词： 均质土质覆盖层单位梯度边界任意初始条件降雨入渗解析解　出处：《岩土工程学报》2017年02期 　论文类型：期刊论文

【摘要】：均质土质覆盖层作为填埋场与大气环境的隔离结构其主要功能是控制雨水入渗,近些年该类覆盖层在北美一些干旱和半干旱地区被证明是有效的。基于二维非饱和土渗流控制方程,采用可考虑土体进气值的指数函数描述土体的土水特征曲线和渗透系数曲线,使用单位梯度边界作为土质覆盖层的底部边界条件,推导出可考虑任意初始条件的降雨入渗移解析解。通过与前人试验结果比较与分析,证明了该解析解的有效性。对比分析了均质土质覆盖层底部分别取单位梯度边界、渗流审查边界和固定孔压边界对降雨入渗及渗漏量的影响,分析结果表明:与渗流审查边界和固定孔压边界相比,单位梯度边界更适合土质覆盖层的渗漏量计算。利用该解析解分析不同初始条件对累计渗漏量的影响,结果表明覆盖层累计渗漏量随其底部初始体积含水率的增加而增大。为土质覆盖层防渗漏性能评价提供了一种简单实用的计算方法。
[Abstract]:The main function of homogeneous soil cover as the isolation structure between landfill and atmosphere environment is to control Rain Water infiltration. In recent years, this kind of overburden has been proved to be effective in some arid and semi-arid areas of North America, based on the governing equation of two-dimensional unsaturated soil seepage. The soil water characteristic curve and permeability coefficient curve are described by the exponential function which can consider the air intake value of the soil, and the unit gradient boundary is used as the bottom boundary condition of the soil cover layer. The analytical solution of rainfall infiltration is derived considering arbitrary initial conditions, and the results are compared with those of previous experiments. The validity of the analytical solution is proved. The unit gradient boundary is taken at the bottom of homogeneous soil cover layer, and the influence of seepage boundary and fixed pore pressure boundary on rainfall infiltration and leakage is analyzed. The results show that the unit gradient boundary is more suitable for the calculation of the leakage of soil cover than the seepage check boundary and the fixed pore pressure boundary. The analytical solution is used to analyze the effect of different initial conditions on the cumulative leakage. The results show that the cumulative leakage of the cover increases with the increase of the initial volume water content at the bottom which provides a simple and practical calculation method for the evaluation of the anti-leakage performance of the soil cover.
【作者单位】：浙江大学软弱土与环境土工教育部重点实验室;同济大学地下建筑与工程系;
【基金】：国家重点基础研究发展计划(“973”计划)项目(2012CB719805)
【分类号】：TU43
【正文快照】： 封场覆盖层作为填埋场与大气环境的隔离结构其主要功能是减少降雨入渗到填埋场内部形成渗滤液。均质土质覆盖层(monolithic cover)是由一层适合植物生长的细粒土组成,此土层通过降雨时存储水分随后植被蒸腾和地表蒸发释放水分的原理控制雨水入渗[1-2]。相比较传统覆盖层(如压

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