渭河河漫滩宏观弥散度计算  

Macrodispersivity Determined for Floodplain Deposits in Weihe River

作　　者：张小筱 李修成 

机构地区：[1]陕西地建土地勘测规划设计院有限责任公司,陕西西安710075 [2]陕西地建土地综合开发有限责任公司,陕西西安710075

出　　处：《水文》2017年第5期21-26,共6页Journal of China Hydrology

基　　金：国家自然科学基金面上项目(41072183)

摘　　要：宏观弥散度的确定对地下水溶质运移至关重要。利用竖管法野外现场测定900个点的垂向饱和渗透系数Kv值,然后进行统计分布检验,运用地质统计学中负指数模型在有块金效应影响的条件下拟合出ln Kv的空间相关尺度λ值,进而利用λ与宏观弥散度关系式求解渭河漫滩非饱和带的宏观弥散度。结果表明,研究区整体Kv平均值为0.012cm/s,方差为1.33,表明Kv空间差异性较大;垂向渗透系数基本服从对数正态分布规律,满足宏观弥散度计算条件;估算整体纵向宏观弥散度为21.27m,各排计算结果约2.11~4.65m。Macrodispersivity is a crucial parameter in analysis of solute transport in groundwater. In this study, we measured 900 vertical hydraulic conductivity（Kv） for floodplain deposits in the Weihe River, China. The Kvvalues were collected from a 30 by 30 grid（an area of 60 m by 45 m） using the standpipe method. The results show that the average Kvvalue of the floodplain deposits is0.012 cm/s, the median value is 0.006 cm/s, and the variance is 1.33, which means that the spatial variation of hydraulic conduc-tivities is notable. The statistical test indicates that these Kvvalues show a log-normal distribution. The exponential variograms were derived to analyze the spatial correlation of these Kvvalues. The macrodispersivity values were then calculated based on the spatial correlation scale and the variance of ln Kv. The calculated longitudinal macrodispersivity for the whole study area is 21.27 m, and the macrodespersivity values for individual rows within the grid area range from 2.11 to 4.65 m.

关 键 词：河漫滩 渗透系数 地质统计学 相关尺度 宏观弥散度 

分 类 号：P641.2[天文地球—地质矿产勘探]