燃煤产物渗滤液作用下改性膨润土的渗透特性研究  

Study on permeability characteristics of modified bentonite under action of coal combustion product leachate

作　　者：张琰 邱金伟 李丹[1,2] 胡波[3] ZHANG Yan;QIU Jinwei;LI Dan;HU Bo(School of Urban Construction,Wuhan University of Science and Technology,Wuhan 430065,China;Hubei Provincial Engineering Research Center of Urban Regeneration,Wuhan University of Science and Technology,Wuhan 430065,China;Key Laboratory of Geomechanics and Geotechnical Engineering of Ministry of Water Resources,Changjiang River Scientific Research Institute,Wuhan 430010,China)

机构地区：[1]武汉科技大学城市建设学院,湖北武汉430065 [2]武汉科技大学城市更新湖北省工程研究中心,湖北武汉430065 [3]长江科学院水利部岩土力学与工程重点实验室,湖北武汉430010

出　　处：《人民长江》2025年第2期209-215,共7页Yangtze River

基　　金：国家自然科学基金项目(52208329);武汉市知识创新专项曙光计划项目(2023020201020359);中央级公益性科研院所基本科研项目(CKSF2023326/YT);安徽省引江济淮集团有限公司科技项目(YJJH-ZT-ZX-20230118528)。

摘　　要：针对天然钙基膨润土防渗性能弱、在盐溶液中防渗性能会急剧劣化的难题,自主研发了一种聚合物改性钙基膨润土。通过渗透试验、自由膨胀指数试验,探究该聚合物改性钙基膨润土在不同离子强度和单价/多价阳离子相对丰度的煤燃烧产物渗滤液作用下的防渗性能,并通过土中结合阳离子浓度变化、XRD测试、SEM测试,研究聚合物改性钙基膨润土的改性机理。结果表明:所提出的聚合物改性钙基膨润土的渗透系数在不同煤燃烧产物渗滤液作用下始终维持在10-11 m/s数量级,表明改性后膨润土的防渗性能显著提升;聚合物改性钙基膨润土在煤燃烧产物渗滤液中仍能维持低渗透性,主要依赖于聚合物的高溶胀性能,而不依赖于膨润土自身的溶胀性能;聚合物改性钙基膨润土中聚合物形成的水凝胶填充了膨润土颗粒间的缝隙,使其结构更加致密,水流通道更加狭窄曲折,导致渗透系数更低。Natural calcium-bentonite has weak impermeability and its impermeability will deteriorate sharply in salt solution.To solve these problems,we develop a polymer to modify calcium-bentonite.Based on permeability test and free expansion index test,the impermeability of the polymer modified calcium-bentonite under the action of coal combustion product leachates with different ionic strength and relative abundance of univalent/polyvalent cations was investigated.The modification mechanism of the polymer-modified calcium bentonite was also analyzed through the changes of binding cation concentration in soil,XRD test and SEM test.The results indicate that the impermeability of proposed polymer modified calcium-bentonite remains 10-11 m/s under the action of coal combustion product leachates,which indicates that the impermeability of bentonite modified by polymer has been improved notably.The proposed polymer modified calcium-bentonite maintaining low permeability in the leachates of coal combustion products mainly depends on the high swelling property of the polymer instead of the swelling property of the bentonite.The hydrogel formed by the polymer in the polymer modified calcium bentonite fills the gaps among bentonite particles,which makes its structure more compact and the water flow channels narrow and tortuous,resulting in lower permeability coefficient.

关 键 词：聚合物 膨润土 渗透性 燃煤产物 渗滤液 

分 类 号：TU443[建筑科学—岩土工程]