豫西丘陵地带黄土介质水动力弥散特性试验研究  

Experimental Research on the Hydrodynamic Dispersion Characteristics of Loess Medium in Hilly Area of Western Henan Province

作　　者：卜新峰 万伟锋 BU Xin-feng;WAN Wei-feng(Yellow River Engineering Consulting Co.Ltd,Zhengzhou 450003,China)

机构地区：[1]黄河勘测规划设计研究院有限公司,郑州450003

出　　处：《中国农村水利水电》2021年第12期27-31,共5页China Rural Water and Hydropower

基　　金：国家重点研发计划资助项目(2018YFC1508703)。

摘　　要：黄土介质特有的垂向发育的微节理、微裂隙等大孔隙使其具有高度的非均质性,为了研究这种空间非均质性对黄土介质弥散能力的影响,结合室内和野外弥散试验的特点和优势,在豫西丘陵地带某试验场地开展了基于两种尺度的黄土介质弥散特性试验研究。研究结果表明:①基于径向收敛流瞬时注入法野外弥散试验获取的黄土介质弥散度数值稳定性较好,获取的代表场地水平方向的纵向弥散系数与平均孔隙流速呈良好的线性关系;②室内土柱淋滤试验表明,非均质土柱的弥散参数显著大于均质土柱,差值达到一个数量级,分析认为黄土介质垂向上发育的微节理、微裂隙等大孔隙是造成黄土介质垂向弥散能力较大的重要原因;③对比室内和野外弥散试验结果表明,黄土介质的空间非均质性在水平和垂直方向的显著差异影响其不同方向的水动力弥散能力,即黄土介质的垂向弥散能力显著大于水平方向。在研究非均匀介质的弥散系数时,应根据试验目的有针对性地选择室内或是野外弥散试验。The vertical development of micro joints,micro fissures and other macropores in Loess make it highly heterogeneous.In order to study the influence of the spatial heterogeneity on the dispersion capacity of loess medium,combined with the characteristics and advantages of indoor and field dispersion tests,two scale tests on the dispersion characteristics of loess medium were carried out at a test site in the hilly area of western Henan Province.The results show that:①The value of the dispersivity obtained by the radial convergent flow instantaneous injection method is stable,and the longitudinal dispersion coefficient representing the horizontal direction of the site has a good linear relationship with the average pore velocity;②The indoor soil column leaching test shows that the dispersion parameters of heterogeneous soil column is significantly larger than that of homogeneous soil column,and the difference reaches an order of magnitude.It is considered that the vertical development of micro joints,micro cracks and other macropores in Loess medium is an important reason for the larger vertical dispersion capacity of loess medium,and its influence on the vertical hydrodynamic dispersion coefficient of loess medium exceeds the degree of non-uniformity of pores and soil column height;③The combination of indoor and field dispersion tests has certain advantages in obtaining horizontal and vertical dispersion parameters of loess media.The comparison of test results show that the significant difference of spatial heterogeneity between horizontal and vertical direction of loess affects its hydrodynamic dispersion capacity,that is,the vertical dispersion capacity of loess is significantly greater than that of horizontal direction.

关 键 词：黄土介质 弥散试验 空间非均质性 垂向水动力弥散参数 

分 类 号：TV138[水利工程—水力学及河流动力学] P641[天文地球—地质矿产勘探]