基于非均匀性和分形维数的黄土优先流特征定量分析

发布时间：2018-11-28 21:12

【摘要】：该文以陕西泾阳南塬边坡黄土为例开展示踪剂试验,通过改进的优先流入渗深度和入渗量非均匀性系数,研究黄土优先流的入渗量、入渗深度、含水率、孔隙率、分形等参数的相互关系及其内在规律。结果表明:1)入渗量越大,优先流入渗深度的非均匀性越明显;2)初始含水率越高,优先流发育程度越低,而湿润锋迹线的分形维数越小;3)黄土孔隙率越大,优先流入渗深度的非均匀性越明显,且入渗深度值波动范围也相对较大;4)同一类型的黄土,其试验尺度大小对湿润锋迹线的分形维数没有明显影响;5)在0.5倍黄土优先流最大入渗深度范围内,分形特征值越大,优先流非均匀程度越强,优先流越发育;6)在没有明显优先流渗流通道情况下,90 mm地表灌溉水量,其最大入渗深度不超过120 cm。考虑正常蒸发和没有裂缝的前提下,地表灌溉水并不容易直接导致地下水位上升。由此推断,优先流在地表水向地下水转换过程中发挥着重要作用。同时,优先流对黄土滑坡的影响不容忽视。研究可为深入揭示黄土优先流渗流特征与黄土优先流滑坡的内在联系提供依据。
[Abstract]:This paper takes loess slope in Jingyang, Shaanxi Province as an example to carry out tracer test. The infiltration amount, infiltration depth, moisture content and porosity of loess preferential flow are studied through improved preferential inflow depth and non-uniformity coefficient of infiltration amount. The interrelation of fractal and other parameters and its inherent law. The results show that: 1) the higher the infiltration amount, the more obvious the inhomogeneity of the preferential infiltration depth, 2) the higher the initial water content, the lower the development degree of the preferential flow, and the smaller the fractal dimension of the wetting front. 3) the larger the porosity of loess, the more obvious the inhomogeneity of preferential inflow depth, and the larger the fluctuation range of infiltration depth, 4) the size of the same type loess has no obvious influence on the fractal dimension of wetting front track. 5) in the maximum infiltration depth range of 0.5 times loess preferential flow, the larger the fractal characteristic value, the stronger the non-uniformity of preferential flow and the more developed preferential flow; 6) under the condition of no obvious preferential flow seepage passage, the maximum infiltration depth of 90 mm surface irrigation water is not more than 120 cm.. Considering normal evaporation and no cracks, surface irrigation water is not easy to cause groundwater level to rise. It is inferred that preferential flow plays an important role in the conversion of surface water to groundwater. At the same time, the influence of preferential flow on loess landslide can not be ignored. The study can provide the basis for revealing the relationship between loess preferential flow seepage characteristics and loess preferential flow landslide.
【作者单位】：黔南民族师范学院旅游与资源环境学院;长安大学环境科学与工程学院;
【基金】：国家自然科学基金项目(40372114) 贵州省教育厅创新群体重大研究项目(黔教合KY字[2016]054);贵州省教育厅创新群体重大研究项目(黔教合KY字[2016]055)
【分类号】：S152.7

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