氧化镁碱激发矿粉-膨润土-土竖向屏障材料阻隔铅污染物的化学渗透膜效应  

Experimental study on chemico-osmotic membrane behaviors of reactive MgO-activated slag-bentonite backfill in vertical cutoff walls exposed to Pb-laden groundwater

作　　者：李双杰 伍浩良 傅贤雷 蒋宁俊[1] 万佳磊 李江山[3] 杜延军[1] LI Shuang-jie;WU Hao-liang;FU Xian-lei;JIANG Ning-jun;WAN Jia-lei;LI Jiang-shan;DU Yan-jun(Institute of Geotechnical Engineering,Southeast University,Nanjing 210096,China;Department of Civil&Environmental Engineering,Hong Kong University of Science&Technology,Hong Kong 999077,China;State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan 430071,China)

机构地区：[1]东南大学交通学院岩土工程研究所,江苏南京210096 [2]香港科技大学土木与环境工程系,中国香港999077 [3]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,湖北武汉430071

出　　处：《岩土工程学报》2022年第6期1078-1086,共9页Chinese Journal of Geotechnical Engineering

基　　金：国家重点研发计划项目(2018YFC1803100,2018YFC1802300);国家自然科学基金项目(41877248,42177133)。

摘　　要：采用活性氧化镁激发粒化高炉矿粉(GGBS)制备氧化镁激发矿粉-膨润土-土(MSBS)竖向阻隔屏障材料。通过一维土柱化学渗透试验,研究了硝酸铅(Pb(NO_(3))_(2))污染液浓度对MSBS阻隔屏障材料的阻隔性能参数包括化学渗透膜效率系数、有效扩散系数和阻滞因子的影响规律,对比分析了MSBS、土-膨润土(SB)和膨润土防水毯(GCL)竖向屏障材料的阻隔性能参数的差异特征。结果表明:MSBS屏障材料在Pb(NO_(3))_(2)污染液中表现出明显的化学渗透膜效应,其化学渗透膜效率系数随着Pb(NO_(3))_(2)污染液浓度增加迅速减小。MSBS阻隔屏障材料Pb^(2+)的有效扩散系数随Pb(NO_(3))_(2)污染液浓度增大略有增加,但变化幅度明显低于SB屏障材料。MSBS的阻滞因子受Pb^(2+)浓度影响不显著,而SB竖向阻隔屏障对于Pb^(2+)的阻滞因子则随其浓度增加而显著降低。The reactive magnesia(MgO)is used as an alkali activator to activate granulated blast furnace slag(GGBS)to prepare alkali activated slag-bentonite-soil vertical barrier(MSBS)material.The chemico-osmotic memberane behavior test using lead nitrate Pb(NO_(3))_(2) solutions with different concentrations as testing liquids is conducted on the MSBS specimen,and the effects of Pb(NO_(3))_(2) concentration on the Pb^(2+) containment performance including chemico-osmotic efficiency coefficient,effective diffusion coefficient and retardation factor are evaluated.Comparative assessment of performance is made between the MSBS material in this study and other engineered barrier materials including soil-bentonite(SB)vertical cutoff wall backfill and geosynthetic clay liner(GCL)reported in previously published studies.The results show that the MSBS backfill has noticeable chemical-osmotic membrane behavior,and the chemico-osmotic efficiency coefficient decreases rapidly with the increasing Pb^(2+) concentration.The effective diffusion coefficient of Pb^(2+) in the MSBS increases slightly with the increasing Pb^(2+) concentration,and its change magnitude is significantly lower than that for the SB backfill materials.The retardation factor for Pb^(2+) in the MSBS backfill remains practically constant with the increasing Pb^(2+) concentration,whereas it decreases significantly with the increasing Pb^(2+) concentration for the SB backfill materials.

关 键 词：MgO-GGBS MSBS 化学渗透膜效应 有效扩散系数 阻滞因子 

分 类 号：TU43[建筑科学—岩土工程]