中文摘要：

介电常数作为描述土壤介电特性的物理量,可以反映土壤的特性。本文采用室内模型试验的方法,以重金属铬（Cr）为例,测定不同含水率、不同污染程度条件下细砂、粉土、黏土3种介质介电常数的变化特征,并分析与判断Cr污染程度、含水率以及土壤颗粒级配对土壤介电常数的影响。试验结果表明：细砂、粉土、黏土3种介质在无污染条件下,控制介质介电常数变化的主要因素是含水率;在加入Cr污染液后,随着Cr离子的进入,3种介质在含水率小于20%时,介电常数平稳增长,当含水率大于20%时,3种介质介电常数出现急剧增长;随着Cr污染浓度的增加,当细砂和黏土介质中污染浓度超过4mg/L、粉土介质中污染浓度超过3mg/L时,3种介质的介电常数出现十分显著的变化;另外,介质颗粒越细、越偏黏性,介质介电常数越大。

英文摘要：

The dielectric constant as to describe the soil dielectric characteristic index can reflect the characteristics of the soil. Based on the method of laboratory model test, taking the heavy metal chromium （Cr） as the example, the changing characteristics of the dielectric constant for the three kinds of media such as fine sand, silty soil and cohesive soil are determined under the different moisture content and different pollution degree, and the influences of the Cr pollution degree, moisture content and soil grain size grading to the soil dielectric constant are analyzed. The testing results show that the moisture content is the main factor to control the changing of dielectric constant for the three kinds of media under the condition of no pollution; after mixing the Cr pollution liquid, with the Cr ions to enter the three kinds of media, the dielectric constant will steadily increase when the moisture content is less than 20% ; when the moisture content is more than 20% , the dielectric constant will sharply increase; with the increase of Cr pollution concentration, when the pollution concentration for the fine sand and clay is more than 4mg/L and the pollution concentration for the silty soil exceeds 3mg/L, the dielectric constant of the three kinds of media will extremely change. In addition, the more fine and more viscous the medium grain is, the larger the dielectric constant is.