中文摘要：

为了全面准确的监测轻非水相液体（LNAPL）在非均质多孔介质中的入渗过程,本文通过室内试验模拟了LNAPL污染物在三维非均质砂槽中的运移,并采用高密度电阻率成像法获得电阻率值随时间的变化过程图.试验结果表明,通过三维电阻率值随时间的变化过程图清晰地反映了LNAPL在非均质多孔介质中的运移过程.在水平方向上,LNAPL污染的中心区域近似为圆形,随着LNAPL的注入量不断增加,被污染区域的范围不断增大,中心区域的电阻率值也不断增大.在垂直方向上,起初的污染区域近似为半圆形,当LNAPL接近介质的突变面时,污染区域的形状从半圆形变为了半椭圆形,即LNAPL的横向运移速度大于纵向运移速度,这种现象说明了位于砂槽中间的细砂透镜体对LNAPL的纵向运移起了阻滞作用,同时使其横向运移速度增大.通过高密度电阻率成像法得到的非均质电阻率值变化图可知,采用高密度电阻率成像法对非均质多孔介质中轻非水相液体的运移进行三维的、动态的监测是可行和有效的.

英文摘要：

For the sake of monitoring the infiltration process of Light Non-Aqueous Phase Liquids（LNAPL）thoroughly and accurately in heterogeneous porous medium.In this paper,we have simulated LNAPL contaminant migration in threedimensional heterogeneous sand tank through indoor experiments,and obtained the variation images of the threedimensional resistivity value that change with the course of time with the help of the Electrical Resistivity Tomography（ERT）method.The experimental results show that the variation process of three-dimensional resistivity value that change with the course of time is able to clearly reflect LNAPL migration process in heterogeneous porous medium.In the horizontal direction,it is obvious that the shape of the center area which is contaminated by LNAPL can be seen as a circular approximately.As the increasing injecting quantity of LNAPL,the scope of contaminated area is increasing.Besides,the resistivity value of the center area is also increasing.In the vertical direction,LNAPL contaminated area can be seen as a semicircular at the beginning of the injection.However,when LNAPL approaches to the mutation surface of the media,the shape of the contaminated area changes from a semicircular to a semi-elliptical.That is to say,the lateral migration speed of LNAPL is greater than the vertical migration. This phenomenon has given a powerful evidence that the fine sand lens in the middle of the three-dimensional heterogeneous sand tank have played a role in blocking for the vertical migration of LNAPL.At the same time,the fine sand lens cause the lateral migration speed of LNAPL to incerase.From the variation images of the three-dimensional resistivity value that change with the course of time under the condition of heterogeneity which is obtained by Electrical Resistivity Tomography method,we can know that it is feasible and efficacious to apply Electrical Resistivity Tomography method to carrying out a three-dimensional dynamic monitoring experiment of LNAPL migration process in the heterogeneo