压实膨润土工程屏障对重金属污染物的阻滞

陈永贵^{1, 2}，贺勇^{1, 2}，周星志³

(1. 长沙理工大学 土木与建筑学院，湖南 长沙，410114；
2. 同济大学 岩土及地下工程教育部重点实验室，上海，200092；
3. 中南大学 地球科学与信息物理学院，湖南 长沙，410083)

摘 要：基于渗透、弥散和阻滞作用，探讨压实膨润土工程屏障对重金属污染物的阻滞效果。建立污染物运移过程的三维对流-弥散计算模型，采用数值分析方法，分析重金属污染物Cr(Ⅲ)在地下水环境中的迁移特性，研究压实膨润土工程屏障对Cr(Ⅲ)的阻滞效果，分析工程屏障厚度等因素对污染物阻滞效果的影响。研究结果表明：当不设置工程屏障时，重金属污染物Cr(Ⅲ)在研究区域中发生了显著迁移，且随着时间的推移，重金属污染物的扩散范围逐渐增大；当在污染源周围设置压实膨润土工程屏障后，重金属污染物被控制在工程屏障上游区域内迁移，工程屏障对重金属污染物的阻滞率可达99%，阻滞效果显著。

关键词：压实膨润土；工程屏障；重金属离子；阻滞效果

Retention of heavy metal ion on engineering barriers of compacted bentonite

CHEN Yong-gui^{1, 2}, HE Yong^{1, 2}, ZHOU Xing-zhi³

(1. School of Civil Engineering and Architecture,
Changsha University of Science and Technology, Changsha 410114, China;
2. Key Laboratory of Geotechnical and Underground Engineering, Ministry of Education,
Tongji University, Shanghai 200092, China;
3. School of Geosciences and Info-Physics, Central South University, Changsha 410083, China)

Abstract:The permeability, diffusion and retention characteristics were employed to analyze the retention mechanism of engineering barriers of compacted bentonite. By establishing 3D flow and transport model which can take convection and dispersion of contaminant into consideration, the contaminant transport characteristics of Cr (Ⅲ) in the groundwater environment was numerically analyzed, and the retention effects of the engineering barriers of compacted bentonite to the Cr (Ⅲ) was also researched. The results show that the migration of Cr (Ⅲ) is obvious in the research region, and the heavy metal contaminant spreads around in the situation without engineering barriers. When the engineering barriers of compacted bentonite were constructed, the contaminant transport can be restricted in the front region of the engineering barriers. The retention efficiency of the engineering barriers to contaminant migration is about 99% in the studied condition.

Key words:compacted bentonite; engineering barriers; heavy metal ion; retention