区域地下水溶质运移随机理论的研究与进展

A Review of Stochastic Analysis for Solute Transport at Regional Scale

在总结近年来国内外区域地下水溶质运动研究的基本理论、方法和部分成果的基础上，论述了溶质在大区域运动的主要影响因素为区域介质的空间变异性。首先总结了野外条件下饱和介质和非饱和介质土壤渗透性能的空间变异性结果，由于野外渗透介质严重的空间变异性，研究溶质在野外条件下的运动采用了随机理论方法。基于Ｌａｇｒａｎｇｅ方法和Ｅｕｌｅｒ方法，研究结果表明，在渗透系数为对数正态二阶平稳及一阶扰动近似条件下，平均浓度满足对流－弥散方程，方程中宏观弥散度决定于介质渗透性能的统计特征，总结了一系列宏观弥散系数的表达形式，在此基础上，指出了需要进一步研究的问题。

Solute transport in heterogeneous formation has been studied with increasing intensity in the past few decades as a result of growing concern about groundwater quality and pollution. The basic theory, methods, and some results are discussed and summarized in this paper. It is widely recognized that the variability of conductivity is the controlling factor for solute transprot at field scale. This paper summarizes some results of the variability of formation and soil hydraulic properties from field experiments. It is shown that the variance of log transformed hydraulic conductivity is closed to 1 and the correlation length increases with the measurement scale. By considering the hydraulic properties as random fields, Lagrangian and Eulerian methods were used to study solute transport in regional scale. The mean concentration satisfies convection dispersion equation with macor scale parameters. The paper also shows some results of concentration variance which is used as a measure of the adequacy of the mean concentration. The results emphasize the key role of variance and correlation length of log transformed conductivity field. Based on this review, we point out some further research fields.