| 不同砂?膨润土垂直防渗墙填筑土料的掺量研究 |
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| 引用本文： | 徐浩青,周爱兆,姜朋明,刘顺青,宋苗苗,陈亮.不同砂?膨润土垂直防渗墙填筑土料的掺量研究[J].岩土力学,2019,40(Z1):424-430. |
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| 作者姓名： | 徐浩青 周爱兆 姜朋明 刘顺青 宋苗苗 陈亮 |
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| 作者单位： | 1. 江苏科技大学 土木工程与建筑学院，江苏 镇江 212003；2. 河海大学 岩土力学与堤坝工程教育部重点实验室，江苏 南京 210098 |
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| 基金项目： | 河海大学岩土力学与堤坝工程教育部重点实验室开放基金项目（No.2018004）；镇江市重点研发计划（社会发展）项目（No.SH2018024）；国家自然科学基金项目（No.51579119）。 |
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| 摘 要： | 土?膨润土垂直防渗墙在美国已广泛应用于城市卫生填埋场中，我国的工程中则应用较少。由国产膨润土与原地层土混合在自重应力作用下固结形成的防渗墙，其渗透性、孔隙和压缩性如何受膨润土掺量的影响，针对该一问题，使用福建标准砂模拟原地层，以3种典型膨润土作为混合料，在各掺量下对砂?膨润土填筑土料开展改进柔性壁渗透试验固结试验，研究不同膨润土掺量对填筑料渗透系数k、孔隙率n与压缩系数av影响。结果表明，膨润土和砂形成防渗墙时存在一个对应最小n和av的最优掺量Copt，当膨润土掺量小于等于Copt时，随着掺量增加，填筑料k下降很快，av缓慢减小；当掺量大于Copt后，随掺量上升，k降低速度趋缓，av快速地升高。理论上，膨润土掺入较少时黏土颗粒仅填充砂粒间的孔隙而不影响砂粒堆积，掺量达到一定程度后膨润土使砂粒彼此分离，悬浮在其中，填筑料的孔隙率随掺量而增大，可能是宏观上造成最优掺量产生的主要原因。
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| 关 键 词： | 防渗墙 膨润土 渗透系数 压缩系数 最优掺量 |
| 收稿时间： | 2019-01-27 |
Study on bentonite content of different sand-bentonite vertical cutoff wall backfill materials |
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| XU Hao-qing,ZHOU Ai-zhao,JIANG Peng-ming,LIU Shun-qing,SONG Miao-miao,CHEN Liang.Study on bentonite content of different sand-bentonite vertical cutoff wall backfill materials[J].Rock and Soil Mechanics,2019,40(Z1):424-430. |
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| Authors: | XU Hao-qing ZHOU Ai-zhao JIANG Peng-ming LIU Shun-qing SONG Miao-miao CHEN Liang |
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| Institution: | 1. School of Architecture and Civil Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212003, China;
2. Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering, Hohai University, Nanjing, Jiangsu 210098, China |
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| Abstract: | Soil-bentonite cutoff walls have been widely used for municipal sanitary landfill in United States. However, there are less engineering applications in China and domestic bentonites and stratum have been mixed and formed to cutoff walls under the consolidation of self-weight stress. Less information is known to how the porosity, permeability and compressibility of cutoff walls are influenced by the addition of bentonite. To solve this problem, the effects of bentonite content on the k, n and av of sand-bentonite backfills are investigated based on several improved flexible wall permeability tests and consolidation tests using Fujian Standard sand as the simulated stratum and three typical bentonite mixtures as additional material. The results show that when bentonites and sand are mixed into cutoff walls, there is a critical bentonite content Copt, where the n and the av are lowest. If the bentonite content is less than or equal to Copt, k decreases rapidly and av reduces slowly with the increase in bentonite content. As the bentonite content is larger than Copt, reduced rate k slows down and av increases rapidly with the increase in bentonite content. In theory, when the bentonite content is much lower, clay particles only fit within the sand pore space and without disturbing the sand pack pattern. However, after bentonite content reaches Copt, sand grains become disconnected and are suspended in the bentonite, resulting in increased porosity of the backfill increases with bentonite content, which may be the main reason of the optimum bentonite content at the macro level. |
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| Keywords: | cutoff wall bentonite hydraulic conductivity coefficient of compressibility optimum bentonite content |
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