土壤有机质对铅污染土固稳特性的影响规律及微观机理  

Effects of organic matter on engineering characteristics and microstructures of lead contaminated soil S/S treated by cement

作　　者：李江山[1] 张亭亭[1] 王平[1] 黄茜[1] 薛强[1] 

机构地区：[1]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,武汉430071

出　　处：《东南大学学报（自然科学版）》2016年第A01期57-62,共6页Journal of Southeast University：Natural Science Edition

基　　金：国家自然科学基金资助项目(41602315;51479194);岩土力学与工程国家重点实验室开放基金课题资助项目(Z015003);中国科学院科技创新"交叉与合作团队"资助项目(Y426011C01)

摘　　要：为了研究有机质对水泥固稳铅污染土特性的影响规律及其作用机制,开展了不同有机质含量(0%,0.5%,1%,2%,5%)铅污染土的固稳试验.通过无侧限抗压强度、渗透和溶出特性试验,探讨了有机质对水泥固稳铅污染土特性的影响规律.结果表明,随着有机质含量的增加,固化土的渗透性和浸出液pH增大,而抗压强度和铅浸出质量浓度降低.通过扫描电镜试验和压汞试验分析了有机质对铅污染土固稳特性影响的微观机制.结果表明,有机质通过阻滞水泥水化反应而使固化土胶结程度减弱,固化土的孔隙增大,渗透性增大且抗压强度降低.重金属与有机质发生络合等化学作用,改变了重金属的赋存形态,降低了重金属的迁移性。Unconfined compressive strength, permeability, leaching, and microstructure tests were conducted to investigate the engineering characteristics and micro-mechanisms of stabilized/solidified （S/S） lead-contaminated soils with different organic matter contents （0%, 0.5%, 1%, 2%, and 5% ）. Results show that the permeability and leaching pH of samples increase with organic matter contents, but the strength and the leaching concentration decrease. Scanning electron microscope （SEM） and mercury intrusion porosity （MIP） tests are conducted to study the micro-mechanisms of the variation of aforementioned properties. Results identify that the organic matter decreases by the quantity and the morphology of cement hydration products by depressing the cement hydration reaction. The quantity of sample pores increases with organic matter contents, the chemical species of heavy metals changed by complexation with organic matter is the reason why the leaching concentration decreases.

关 键 词：铅污染土 固化/稳定化 有机质 微观机制 

分 类 号：U416[交通运输工程—道路与铁道工程]