基础理论与实验研究

NaCl侵蚀环境下水泥固化铬污染土的强度及淋滤特性

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  • 合肥工业大学 资源与环境工程学院,安徽 合肥 230009
刘晶晶,女,1989年生,博士,主要从事环境岩土工程方面的科研工作。

收稿日期: 2015-01-04

  网络出版日期: 2018-06-13

基金资助

国家自然科学基金资助项目(No. 41172273,No. 41372281,No. 40802079)。

Strength and leaching characteristics of chromium polluted soil solidified with cement in a NaCl erosion environment

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  • School of Resources and Environmental Engineering, Hefei University of Technology, Hefei, Anhui 230009, China

Received date: 2015-01-04

  Online published: 2018-06-13

摘要

日益严重的环境污染问题导致土壤中的重金属离子越来越多,这不仅使得土的工程性质受到影响,而且有害重金属离子的渗出也会威胁人类的健康。目前常采用水泥固化技术(S/S法)来处理重金属污染土。但当地下水中富含侵蚀性盐离子时,固化后的重金属污染土会受到影响,进而改变其强度及重金属离子的滤出特性。通过系统的室内试验,对水泥固化铬污染土在NaCl溶液浸泡后的强度特性及重金属离子的滤出特性进行了研究。试验结果表明,水泥固化铬污染土的无侧限抗压强度随NaCl溶液浓度的增加而减小,而随浸泡时间的增加呈先减小后增大的趋势,浸泡7 d时最小。毒性特征沥滤试验(TCLP)结果显示,浸出液中Cr3+浓度随NaCl浓度增加而增大,随浸泡时间增加而减小;而浸出液的pH值随NaCl浓度增加而减小,随着浸泡时间的增加呈先减小后增大的趋势,浸泡7 d时最小;浸出液的pH值在4.0~5.5范围内时,Cr3+滤出量随pH值增大而减小。

本文引用格式

刘晶晶,查甫生,郝爱玲,张雪芹,崔可锐 . NaCl侵蚀环境下水泥固化铬污染土的强度及淋滤特性[J]. 岩土力学, 2015 , 36(10) : 2855 -2861 . DOI: 10.16285/j.rsm.2015.10.015

Abstract

The problem of environmental pollution results in the accumulation of heavy metal ion in soil, which not only influences the engineering properties of soil, but also threatens the health of human beings. Currently the cement solidification technology (S/S method) is adopted to treat heavy metal-contaminated soils. However, with the increase of concentration of corrosive salt in the groundwater, the solidified heavy metal-contaminated soil can be influenced by the corrosive salt ions, resulting in the deterioration of the strength of soil and leaching-out of the heavy metal ions. A series of systematic laboratory tests is conducted to investigate the strength and leaching characteristics of chromium polluted soil solidified with cement after soaking in NaCl solution. The experimental results show that the unconfined compressive strength of chromium polluted soil solidified with cement decreases with the increase of the concentration of NaCl solution, and decreases at first and then increases with soaking time, and the minimum strength is determined after 7 d soaking. The results of the toxicity characteristics leaching procedure (TCLP) show that the concentration of Cr3+ in leachate increases with the increase of NaCl concentration, and decreases with the increase of soaking time. The pH value of leachate decreases with the increase of NaCl concentration, and decreases at first and then increases with soaking time, and the minimum concentration of Cr3+ is got when soaking 7 d. when the pH value of leachate is within the range of 4.0 to 5.5, the leaching quantity of Cr3+ decreases with the increase of pH value.
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