| 无机盐溶液作用下砂-膨润土竖向隔离屏障材料化学相容性试验研究 |
| |
| 引用本文： | 范日东,杜延军,刘松玉,杨玉玲.无机盐溶液作用下砂-膨润土竖向隔离屏障材料化学相容性试验研究[J].岩土力学,2020(3):736-746. |
| |
| 作者姓名： | 范日东 杜延军 刘松玉 杨玉玲 |
| |
| 作者单位： | 东南大学岩土工程研究所;东南大学江苏省城市地下工程与环境安全重点实验室 |
| |
| 基金项目： | 国家重点研发计划(No.2018YFC1803101);国家自然科学基金项目(No.41877248);江苏省科技发展计划项目(No.BE2017715);中国博士后科学基金(No.2018M642143);中央高校基本科研业务费专项(No.2242019R20033)。 |
| |
| 摘 要： | 土-膨润土竖向隔离屏障广泛应用于城市工业污染场地。化学溶液作用下屏障材料的化学相容性,即渗透系数及其变化程度,是评价防污性能的关键因素。通过柔性壁渗透试验研究重金属铅-锌复合、六价铬作用下砂-膨润土竖向隔离屏障材料渗透系数的变化规律。由于无机盐溶液中铅、锌、钙对膨润土双电层的压缩,铅-锌复合、钙溶液作用下屏障材料试样渗透系数随金属浓度升高而增大。铅-锌复合作用下,金属浓度增至500mmol/L时试样渗透系数增幅达11倍,且无法满足防渗要求。相反,由于铬以阴离子络合形式存在,其对试样渗透系数影响相对小;与未污染状态测定结果相比,渗透系数增幅≤2倍。在膨润土孔隙比基础上,考虑无机盐溶液对膨润土膨胀特性的影响,建立无机盐溶液作用前后砂-膨润土竖向隔离屏障材料渗透系数统一预测方法。
|
| 关 键 词： | 膨润土 竖向隔离屏障 无机盐 渗透系数 预测方法 |
Experimental study on chemical compatibility of sand-bentonite backfills for vertical cutoff barrier permeated with inorganic salt solutions |
| |
| FAN Ri-dong,DU Yan-jun,LIU Song-yu,YANG Yu-ling.Experimental study on chemical compatibility of sand-bentonite backfills for vertical cutoff barrier permeated with inorganic salt solutions[J].Rock and Soil Mechanics,2020(3):736-746. |
| |
| Authors: | FAN Ri-dong DU Yan-jun LIU Song-yu YANG Yu-ling |
| |
| Institution: | (Institute of Geotechnical Engineering,Southeast University,Nanjing,Jiangsu 210096,China;Jiangsu Key Laboratory of Urban Underground Engineering and Environmental Safety,Southeast University,Nanjing,Jiangsu 210096,China) |
| |
| Abstract: | Soil-bentonite vertical cutoff wall is extensively applied to containment of urban industrial lands.Chemical compatibility of soil-bentonite backfill exposed to chemical solutions,i.e.,hydraulic conductivity and its amplitude,is of importance to evaluate containment performance.Chemical compatibility of sand-bentonite backfill permeated with lead-zinc mixture(Pb-Zn),hexavalent chromium(Cr(VI)),and calcium(Ca)solutions was studied via flexible wall permeability test.The resulting hydraulic conductivity of the backfill permeated with Pb-Zn and Ca solutions considerably increases compared with the result obtained from uncontaminated specimen due to the squeeze of the double layer around bentonite particles.The hydraulic conductivity can not meet the requirement of anti-seepage when Pb-Zn concentration increased to 500 mmol/L.In contrast,limited increase in hydraulic conductivity is found when the backfill is permeated with Cr(VI)solutions.This is attributed to the fact that Cr(VI)exists in anionic complex rather than exchangeable cation.Predicting method for hydraulic conductivity of sand-bentonite backfills is developed based on the concept of bentonite void ratio and swell index of bentonite exposed to the corresponding inorganic solution. |
| |
| Keywords: | bentonite vertical cutoff barrier inorganic salt hydraulic conductivity predictive method |
| 本文献已被 CNKI 维普 等数据库收录！ |
|
