摘要
长久以来有色金属矿山的开采对矿山周围土体造成了严重的重金属污染问题。使用自制的重金属淋滤污染装置,制备室内重金属Zn^(2+)污染土,进行固结不排水三轴剪切试验,研究淋滤条件下重金属Zn^(2+)对桂林红黏土强度及其强度损伤规律的影响。试验结果表明:重金属Zn^(2+)对桂林红黏土的强度损伤行为是明显的,抗剪强度平均下降了30.61%~56.6%不等,应力-硬化关系均呈现应变硬化型,损伤变量D在0.478~0.566之间。淋滤条件下重金属Zn^(2+)对桂林红黏土强度的损伤主要是由于Zn^(2+)对红黏土胶结结构以及土颗粒的双电层结构产生了不可逆的侵蚀破坏,降低土体内部的联结强度,随着浓度的增大,其强度呈现出下降的趋势,其损伤变量亦有所增长,但相差较小。这是因为在长时间的淋滤过程中,红黏土对Zn^(2+)具有一定的吸附作用,导致尽管是在低浓度的污染溶液淋滤作用下,土体的累积损伤和高浓度的效果相近似。
The exploitation of non-ferrous metal mines has caused serious heavy metal pollution to the surrounding soil. The effect of heavy metal Zn2＋on the strength and strength damage of Guilin red clay under leaching condition is studied using the self-made heavy metal leaching pollutant device. The indoor heavy metal Zn2＋contaminated soil is prepared with consolidation undrained triaxial shear test. The results show that the strength damage behavior of heavy metal Zn2＋to Guilin red clay is obvious. The shear strength is decreased by 30. 61%~ 56. 6%on average. The stress hardening relationship is strain hardening. The damage variable D is between 0. 478 ~ 0. 566. The damage of Zn2＋to Guilin red clay under leaching condition is mainly due to the irreversible erosion damage of the double claylayer and the double-layer structure of red clay. The strength of Zn2＋is decreased with the increase of Zn2＋concentration. The damage variable also increases,but the difference is small. This is because red clay has a certain adsorption effect on Zn2＋during prolonged leaching process,which leads to the similar effect of cumulative damage and high concentration of the soil,even under low concentration of contaminated solution leaching.
出处
《工程地质学报》
CSCD
北大核心
2017年第5期1264-1269,共6页
Journal of Engineering Geology
基金
广西高校科学研究项目(KY2015YB119)
国家自然科学基金项目(41762022)
广西岩溶动力学重点实验室开放课题基金(KDL201604)
广西重点实验室基金(11-kf-02)(12-A-01-02)(11-CX-01)资助
