油水二相体对油污染土电阻率特性的影响

Influences of water and oil two-phase on electrical resistivity of oil-contaminated soils

为研究油类污染粉质黏土的电阻率特性,室内分别拌制了不同含水率、不同含油率的柴油、煤油污染土试样,采用四电极方法对不同状态下的污染土体电阻率进行了测试。试验结果显示,两种油污染土有相似的变化规律,即在相同的含水率下,均表现为电阻率随着含油率的增加而线性增大;在相同的含油率下,随着含水率、水饱和度的增加而呈幂函数关系减小。为了分析油、水二相体对电阻率的影响,引入了体积含湿率、油水饱和度两个指标,发现在相同的水饱和度下,电阻率随体积含湿率的增加而线性增大;在相同的体积含湿率下,电阻率随油水饱和度的增加而幂函数关系减小。进一步分析表明,电阻率与体积含湿率间存在线性相关关系,与油水饱和度间存在幂函数相关关系,两种油污染土的电阻率与体积含湿率、油水饱和度间的关系可以用同一公式表达。

In order to study the electrical resistivity of oil-contaminated soils, the diesel-contaminated soils and soils with different water contents, oil contents are mixed in the laboratory by hand. The four electrode method is used to measure the electrical resistivity of these soils. The results show that two types of oil-contaminated soils have following similar trends： under the same water content, the resistivity of both contaminated soils increases linearly with the increase of oil content; while under the same oil content, the resistivity of these soils decreases in power function with the increase of water content and water saturation degree. In addition, two indexes of volume moisture content, water and oil saturation degree are introduced here to study the influences of water and oil two-phase on the resistivity of oil-contaminated soils. Under the same water saturation degree, it is found that the resistivity of contaminated soils increases linearly with the increase of volume moisture content; while under the same volume moisture content, the resistivity of which decreases in power function with the increase of water and oil saturation degree. Ftmhermore, a linear relationship between the resistivity and the volume moisture content as well as a power function relationship between the resistivity and the water and oil saturation degree of these soils is observed. For both types of oil-contaminated soils, they can be calculated by the same formula.