水泥固化铅污染土的电阻率特性与经验公式

为探讨电阻率法在水泥固化重金属污染土性能评价中的应用潜能,室内配制人工铅污染土,采用水泥固化后测试其电阻率和无侧限抗压强度,分析固化土电阻率的变化规律,建立固化铅污染土的电阻率公式,并探讨电阻率与无侧限抗压强度的相关关系。试验结果表明,固化土电阻率随铅含量增大而减小,随着水泥掺入量和养护龄期的增加而增大,随着孔隙率和饱和度的减小而增大。提出了一个能够综合反映铅含量、水泥掺入量和养护龄期等因素对固化土电阻率影响规律的表征参数(nt·Pb100ew)/(aw·T0.5),用该参数替换Archie电阻率公式中的孔隙率,得到了水泥固化重金属污染土的电阻率经验公式,将Archie电阻率公式扩展应用到固化重金属污染土领域。固化土电阻率与强度之间近似服从幂函数关系。电阻率法是一种有效的重金属污染土固化效果评价方法,且其具有快捷、无损等优势,可推广应用。

Characteristics and empirical formula of electrical resistivity of cement-solidified lead-contaminated soils

In order to explore the application potential of electrical resistivity method in the field of solidified heavy metal-contaminated soils, the artificial contaminated soils with five different lead contents are solidified using cement, and then their electrical resistivities and unconfined compressive strengths after various curing periods are tested. The relationship between the electrical resistivity and unconfined compressive strength is discussed. The test results show that the cement hydration reaction results in an increase of the electrical resistivity of solidified samples, but the electrical resistivity decreases with the increase of after-curing porosity, degree of saturation and lead content. A key parameter (n_t·)/ (a_w·T^0.5) (e is the Euler’s number) is proposed to comprehensively reflect the effects of the lead content, cement hydration reaction and dense state of soils on the electrical resistivity of solidified soils. The Archie’s electrical resistivity formula is extended to solidified heavy metal-contaminated soils by replacing the porosity by the key parameter. There is a power function relationship between the strength and the electrical resistivity while the lead content of solidified soils is certain. The electrical resistivity method can be used as a non-destructive, economical and continuous way to evaluate the quality of solidified heavy metal-contaminated soils.