摘要
针对膨润土防水毯(geosynthetic clay liner,GCL)用于湖底防渗时湖泊溶液离子影响GCL渗透系数的问题,提出用模拟湖泊溶液作为渗透液研究GCL的防渗性能。配置浓度为0.005~1 mol/L的KCl、CaCl2、NH4CL及相互混合溶液作为介质渗透液,以去离子水作为对比渗透液,取出GCL中的膨润土,测试渗透液下膨润土的自由膨胀指数;在相同的渗透液条件下,测试GCL的渗透系数;渗透试验后取出GCL中膨润土分析其元素变化。结果表明:1)相对于介质渗透液,去离子水中GCL的防渗性能最好,渗透系数最小。2)GCL处于渗透液环境时,GCL的防渗性能与膨润土的胀缩性表现出相反的变化趋势。相同浓度的单一渗透液下,GCL渗透系数的规律为NH4Cl<KCl<CaCl2;同一离子强度的混合渗透液下,GCL抗渗性能的规律为KCl+NH4Cl>NH4Cl+CaCl2>KCl+CaCl2。3)在同一种渗透液下,GCL防渗性能对离子浓度的敏感性分为3个区段,分别为浓度<0.1 mol/L、0.1 mol/L<浓度<0.5 mol/L、浓度>0.5 mol/L。GCL防渗性能随渗透液离子浓度的升高而降低,下降幅度不断减缓。4)GCL的防渗性能可以用GCL的元素变化来解释,经渗透液渗透后GCL内的钠元素越少,GCL的抗渗能力越弱。研究结果阐明了湖泊溶液对GCL防渗效果的影响及其机理,可为GCL用于湖泊防渗提供理论依据。
In view of the effect of lake ions on geosynthetic clay liner(GCL)permeability coefficient when GCLs used for the prevention of lake-bottom seepage,a simulated lake solution was proposed to study the anti-seepage performance of GCL.KCl,CaCl2,NH4Cl,and their mixed solutions of 0.005~1 mol/L were used as mediums osmotic solution.Deionized water was used as the contrast osmotic solution.The bentonite was taken from GCL and its free expansion index was tested under the osmotic solution.The permeability coefficient of GCL was measured under the same permeable condition.After permeation test,bentonite in GCL was taken out to analyze its element change.The results indicate the following rules:1)When compared with the ionic solution,GCL exhibits the lowest permeability coefficient and optimal anti-seepage performance in deionized water;2)When the ionic solution acts on the GCL,the permeability coefficient of the GCL exhibits an opposite law to the free swelling index of GCL bentonite;Under the same concentration of a single solution,the law of permeability coefficient of GCL corresponds to NH4Cl<KCl<CaCl2;Under the mixed solution of the same ionic strength,the GCL law of anti-permeability corresponds to KCl+NH4Cl>NH4Cl+CaCl2>KCl+CaCl2.3)Under the same solution,the sensitivity of the GCL anti-seepage performance to the solution concentration is divided into three sections,which are less than 0.1 mol/L,from 0.1 to 0.5 mol/L,and exceeds 0.5 mol/L;The GCL anti-seepage performance decreases with increasing ion concentration;4)The anti-seepage performance of a GCL is explained by the elemental changes in GCL bentonite;Moreover,a decrease in the sodium element content in GCL bentonite after solution penetration weakens the GCL anti-seepage performance.The results show the influence of lake solution on GCL anti-seepage effect and analyze its mechanism,which provides theoretical basis for GCL to be used in lake seepage control.
作者
万娟
赵宏博
肖衡林
程莹
何俊
陶高梁
WAN Juan;ZHAO Hongbo;XIAO Henglin;CHENG Ying;HE Jun;TAO Gaoliang(Technology Research Center of Ecological Road Engineering, Hubei University of Technology, Wuhan 430068, China)
出处
《中国科技论文》
CAS
北大核心
2021年第4期422-429,共8页
China Sciencepaper
基金
国家科技重大专项(2016YFC05022208)
国家自然科学基金资助项目(51608182,41772332)
湖北省中央引导地方科技发展专项(2019ZYYD053)。
关键词
防渗性能
膨润土防水毯
自由膨胀
离子浓度
元素分析
anti-seepage performance
geosynthetic clay liner(GCL)
free swelling index
ion concentration
elemental analysis
