重金属锌污染砂的交流电阻率特性试验

摘要

In order to explore the feasibility of AC resistivity method for monitoring zinc contaminated soil, the resistivity of zinc contaminated sand was tested,and the influences of current frequency,water content,void ratio and zinc contamination content on sand resistivity were analyzed.Therefore,an AC resistivity empirical formula of zinc contaminated sand was proposed.The results indicated that the resistivity decreased rapidly with the increase of current frequency,whereas gradually stabilized when the current frequency was higher than 50 kHz.When zinc content was lower than 50 mg/kg,the electrical resistivity was more sensitive to the change of current frequency.Then,The electrical resistivity decreased with the increase of water content,and lower the water content was,more quickly the resistivity changed. The resistivity increased slowly with the increase of the void ratio,and decreased rapidly with the increase of zinc content.Whereas it gradually stabilized when the zinc content was higher than 250 mg/kg.There was a highly relevant power function relationship between resistivity and zinc content.Based on saturation, void ratio and zinc content,an electrical resistivity empirical formula was proposed.%为研究交流电阻率法检测重金属锌污染的可行性，通过对不同的锌污染砂试样进行电阻率测试，分析了电流频率、含水量、孔隙比、锌污染含量等对砂电阻率的影响，建立了影响锌污染砂交流电阻率的经验公式。结果表明，电阻率随电流频率的增加先急速降低，当电流频率增加到50 kHz 时，电阻率逐渐趋于稳定；以锌含量50 mg／kg 为界，锌含量越低，电阻率对电流频率的变化越敏感；电阻率随含水量的增加而减小，含水量越低，电阻率变化越快；电阻率随孔隙比的增加而增大，增幅较缓；电阻率随锌含量的增大而急速减小，当锌含量高于250 mg／kg 后，电阻率逐渐趋于稳定；砂电阻率与锌污染含量间呈现高度相关的幂函数关系，得出了包含饱和度、孔隙率、锌污染含量的砂交流电阻率关系公式。