摘要
陕西黄土受到不同程度的重金属污染,污染区主要位于陕西关中地带。此外,黄土中主要的重金属离子为铅离子、铜离子、镍离子、镉离子及砷离子,其中铅离子浓度最高,最高浓度达545.6 mg/kg。为防止已污场地污染扩散,拟采用黄土/膨润土隔离墙对场地进行隔离,为此通过试验研究了隔离墙的渗透与防污阻滞性。结果表明,随着隔离墙中膨润土掺量的增加,墙体渗透系数k和防污阻滞系数Cad均大幅降低。为便于隔离墙后续工程设计,提出了定量表征公式,用于预测k与Cad。基于表征公式计算了为达到墙体渗透要求时的最低膨润土掺量,数值为28.52%,超过了工程规定值,因此需对膨润土进行改性处理。与此同时,隔离墙在污染液渗流过程中存在胶体迁移,诱发污染离子扩散与墙体防污阻滞系数降低。后续研究中应针对隔离墙中的胶体,研发一种廉价改性材料,主要用于提高其细度和降低其迁移性,这样才能在降低隔离墙渗透系数和提高防污阻滞系数的同时,还能避免胶体迁移诱发的污染扩散问题。
The loess in Shaanxi Province exhibits heavy metal contamination,primarily concentrated in the Guanzhong region.In addition,the main heavy metal ions in loess are Pb,Cu,Ni,Cd and As.Among them,the Pb concentration is the highest,reaching up to 545.6 mg/kg.To mitigate pollution spread at contaminated sites,a loess/bentonite cutoff wall was implemented,and its hydraulic conductivity and pollution retardation behavior were experimentally investigated.Experimental results demonstrate that increasing bentonite content in the cutoff wall significantly reduces both hydraulic conductivity(k)and pollution retardation coefficient(Cad).To aid in subsequent engineering design,quantitative models for predicting k and Cad were formulated.Using this characterization,the minimum bentonite addition required to meet cutoff wall permeability standards was calculated(28.52%),exceeding the project’s specified value.Consequently,bentonite modification is necessary.Simultaneously,colloid migration during polluted liquid seepage through the cutoff wall was identified,contributing to pollution diffusion and pollution retardation coefficient reduction.Consequently,subsequent research should focus on developing a cost-effective modified material to enhance colloid fineness and reduce its mobility within the cutoff wall.This approach would reduce hydraulic conductivity,improve pollution retardation coefficient,and prevent pollution spread caused by colloid migration.
作者
吴子龙
俞韬
闫超
邓永锋
胡广青
高宇航
王璋
王力
WU Zi-long;YU Tao;YAN Chao;DENG Yong-feng;HU Guang-qing;GAO Yu-hang;WANG Zhang;WANG Li(School of Architecture and Civil Engineering,Xi’an University of Science and Technology,Xi’an,Shaanxi 710054,China;College of Civil Engineering,Anhui Jianzhu University,Hefei,Anhui 230601,China;School of Transportation,Southeast University,Nanjing,Jiangsu 211189,China;Exploration Research Institute of Anhui Coalfield Geology Bureau,Hefei,Anhui 230088,China;Anhui Green Mine Engineering Research Center,Hefei,Anhui 230088,China;China Power Construction Northwest Survey and Design Institute Co.,Ltd.,Xi’an,Shaanxi 710065,China)
出处
《岩土力学》
北大核心
2025年第9期2738-2748,共11页
Rock and Soil Mechanics
基金
国家自然科学基金(No.42302324)
陕西省自然科学基金(No.2022JQ-307)
安徽省智能地下探测技术研究院开放基金(No.AHPZY2023ZR01)
安徽省绿色矿山工程研究中心开放基金(No.AGMERC-23KC-09)。
关键词
黄土重金属污染
黄土/膨润土隔离墙
渗透与防污阻滞性
定量表征
胶体迁移
loess heavy metal pollution
loess/bentonite cutoff wall
hydraulic and pollution prevention retardation behavior
quantitative characterization
colloid migration
作者简介
第一作者:吴子龙,男,1990年生,博士,副教授,主要从事岩土工程方面研究工作。E-mail:xustwzl@xust.edu.cn。
