快速测量非饱和土渗透系数的湿润锋前进法适用性研究

发布时间：2018-01-20 08:49

本文关键词： 非饱和土非饱和渗透系数湿润锋前进法瞬时截面法　出处：《岩土力学》2014年05期 　论文类型：期刊论文

【摘要】：非饱和土渗透系数函数是非饱和土体渗流分析中必不可少的参数。然而非饱和土渗透系数函数测量非常困难,其中稳态法测量范围过于狭小,而瞬时截面法耗时动辄数月,难以应用。为此,提出了湿润锋前进法,有望在一周内测得渗透系数函数。采用数值模拟手段检验湿润锋前进法的测量精度和适用范围。数值模拟结果显示:对于砂土、粉土、黏土,湿润锋前进法得到的渗透系数函数均与输入的理论渗透曲线一致,但测量范围限于高吸力范围(大于进气值)。此外,还采用瞬时截面法计算了渗透系数函数,结果表明:瞬时截面法计算的渗透系数在理论渗透曲线附近波动,其精度取决于监测截面的间距,间距越大,精度越低。在给出的20、60、100 mm这3种间距中,20 mm间距时计算得到的渗透系数精度最高,但与湿润锋前进法的精度仍有一定差距。因此,湿润锋前进法是一种可靠的能够快速得到渗透系数函数的测量手段。
[Abstract]:The permeability coefficient function of unsaturated soil is an essential parameter in the seepage analysis of unsaturated soil. However, it is very difficult to measure the permeability coefficient function of unsaturated soil, and the measurement range of steady state method is too narrow. The instantaneous cross section method takes many months and is difficult to be applied. Therefore, a wet front forward method is proposed. It is expected that the permeability coefficient function will be measured within one week. The accuracy and applicable range of the wetting front advance method will be tested by numerical simulation. The results of numerical simulation show that: for sand silt clay. The permeability coefficient function obtained by the wetting front forward method is consistent with the theoretical permeability curve, but the measurement range is limited to the range of high suction (larger than the inlet air value). In addition, the permeability coefficient function is calculated by the instantaneous cross section method. The results show that the permeability coefficient calculated by the instantaneous section method fluctuates near the theoretical permeation curve, and its precision depends on the spacing of the monitoring section. The greater the spacing, the lower the accuracy. The accuracy of the permeability coefficient calculated at the distance of 20 mm between 100 mm and 20 mm is the highest, but there is still a certain gap between the accuracy of the method and the method of wetting front advance. The wet front forward method is a reliable method to get the permeability coefficient function quickly.
【作者单位】：武汉大学水资源与水电工程科学国家重点实验室;北京交通大学土木建筑工程学院;北京航空航天大学交通科学与工程学院;空军第一建筑安装工程总队;
【基金】：水资源与水电工程科学国家重点实验室开放基金资助项目(No.2010B075) 教育部新教师基金(No.20110009120022)
【分类号】：TU411.4
【正文快照】： 1引言在自然界和工程实践中所遇到的土体大多处于非饱和状态,其非饱和强度、变形和渗透特性等方面的研究受到广泛关注。非饱和土体渗流分析是土体稳定性评价、土体污染物运移分析、岩土隔离层性能评价等工作的基础。非饱和土渗透系数是进行土体渗流分析的核心参数。非饱和土渗

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