基于线性吸附效应的压实黏土衬垫非饱和渗透特性  

Unsaturated Permeability of Compacted Clay Liner Under Linear Adsorption Condition

作　　者：陈永贵[1,2] 周星志[3] 叶为民[1] 贺炜[2] 

机构地区：[1]同济大学岩土及地下工程教育部重点实验室,上海200092 [2]长沙理工大学土木与建筑学院,湖南长沙410114 [3]中南大学地球科学与信息物理学院,湖南长沙410083

出　　处：《同济大学学报（自然科学版）》2012年第3期390-395,共6页Journal of Tongji University:Natural Science

基　　金：国家自然科学基金(40802064,50908024);上海市教育委员会科研创新项目(12ZZ032);上海市重点学科建设项目(B308);湖南省教育厅资助科研项目(11A010)

摘　　要：压实黏土衬垫(CCL)作为卫生填埋场最主要的防渗措施,其主要组成成分为粘性土体,在阻渗过程中会吸附渗滤液中的污染物质,改变土体孔隙结构,显著影响CCL防渗性能.假定CCL土体对污染物的吸附服从线性模式,土中孔隙均匀分布,土孔隙体积的改变只受污染物吸附效应影响,基于质量和体积关系分析,建立考虑污染物吸附效应的非饱和渗流模型,采用数值方法分析CCL对污染物的吸附效应对其非饱和渗透系数的影响.结果表明,填埋场CCL对污染物的吸附作用可有效降低防渗系统孔隙率,显著提高CCL防渗性能.在考虑吸附效应条件下,吸附分配系数、污染物浓度、初始孔隙率和有效饱和度等参数对CCL非饱和渗透性能有较大影响.The compacted clay liner（CCL）,the main anti-seepage facilities in landfill and mainly made up of clayey soil,will adsorb the contaminants of the leachate when it prevents the leachate from polluting the groundwater and surrounding soils.The permeability of the CCL is affected by its microscopic pore structure changes due to the adsorption of clay.It is assumed that the adsorption of contaminants on the CCL be in accordance with the linear model,the pore distribution in the CCL be uniform and only affected by the adsorption.Based on the conservation of volume and mass,an empirical formula was presented for CCL to evaluate the changes of porosity induced by the adsorption.Meanwhile,a new unsaturated permeability model was also proposed with a consideration of the adsorption effects of contaminants on the CCL pore structure.Finally,the effects of adsorption of CCL on its unsaturated permeability were analyzed by numerical calculation.The results show that the adsorption of contaminants on CCL can reduce the porosity and improve the performance of seepage-prevention of CCL.Taking the adsorption effects into account,the unsaturated permeability of the CCL is significantly affected by the adsorption distribution coefficient,contaminant concentration,initial porosity and effective saturation.

关 键 词：压实黏土衬垫 吸附效应 微观孔隙结构 非饱和渗透系数 

分 类 号：TU42[建筑科学—岩土工程]