水泥-粉煤灰固化/稳定重金属污染土的电阻率特性试验研究  

Electrical resistivity of heavy metal contaminated soils solidified/stabilized with cement-fly ash

作　　者：查甫生[1] 刘晶晶[1] 许龙[1] 邓永锋[2] 杨成斌[1] 储诚富[1] ZHA Fu-sheng;LIU Jing-jing;XU Long;DENG Yong-feng;YANG Cheng-bin;CHU Cheng-fu(School of Resources and Environmental Engineering,Hefei University of Technology,Hefei,Anhui 230009,China;Institute of Geotechnical Engineering,Southeast University,Nangjing,Jiangsu 210096,China)

机构地区：[1]合肥工业大学资源与环境工程学院,安徽合肥230009 [2]东南大学岩土工程研究所,江苏南京210096

出　　处：《岩土力学》2019年第12期4573-4580,4606,共9页Rock and Soil Mechanics

基　　金：国家自然科学基金（No.41672306,No.41877262,No.41572280,No.41372281）~~

摘　　要：固化/稳定法修复重金属污染土固化机制的研究方法多基于力学测试和化学分析,因而提出无损、快捷方便且经济有效的物理评价方法是目前亟待解决的关键问题。通过系统的室内试验,利用电阻率法研究了水泥-粉煤灰固化重金属污染土的微观作用机制,并建立了基于电阻率的固化铅污染土无侧限抗压强度预测模型。试验结果表明,随着养护龄期的增加,试样电阻率、孔隙水电阻率、结构因子、形状因子均显著增大,而各向异性系数则随之减小。而增加重金属离子浓度,电阻率、孔隙水电阻率以及平均形状因子明显减小,各向异性系数A则逐渐增大。扫描电镜分析结果与电阻率参数变化规律吻合,进一步验证了电阻率法揭示水泥-粉煤灰固化重金属污染土微观作用机制的可行性。此外,电阻率与无侧限抗压强度之间存在良好的线性关系,可作为评价固化土体力学性能的指标。Most of researches related to the immobilization mechanisms of stabilized/solidified heavy metal contaminated soils were depended on the mechanical tests and chemical analysis. Thus, proposing a physical method that is un-destructive, time-saving, convenient and cost-effective is the urgent issue to be solved currently. In this paper, a series of laboratory tests including electrical resistivity test was performed to investigate the microstructural mechanism of cement-fly ash stabilized heavy metal contaminated soils. Furthermore, the prediction model of unconfined compressive strength was established based on the electrical resistivity. The tests results presented that with increasing of curing time, electrical resistivity, pore water electrical resistivity, structure factor, as well as shape factor of the specimens increased, and the anisotropy coefficient decreased. While increasing the heavy metal ions concentration leaded to an obvious reduction in electrical resistivity, pore water electrical resistivity and shape factor, and the anisotropy coefficient increased gradually. The SEM results was consistent with that of the electrical resistivity, which confirmed the feasibility that revealing the microstructural mechanism of the stabilization/solidification of heavy metal contaminated soils by electrical resistivity method. Finally, a good linear relationship between the electrical resistivity and unconfined compressive strength can be obtained. It is suggested that the electrical resistivity can be used as the index to evaluate the mechanical properties of the stabilized soil.

关 键 词：重金属污染土 固化/稳定法 电阻率 无侧限抗压强度 微观机制 

分 类 号：TU449[建筑科学—岩土工程]