Limiting membrane behavior of compacted sand-bentonite mixture  

作　　者：Cameron J.Fritz Joseph Scalia IV Charles D.Shackelford 

机构地区：[1]Stantec Consulting Services,Inc.,Fort Collins,CO,80525-2903,USA [2]Department of Civil and Environmental Engineering,Colorado State University,Fort Collins,CO,80523-1372,USA

出　　处：《Journal of Rock Mechanics and Geotechnical Engineering》2025年第4期2433-2444,共12页岩石力学与岩土工程学报(英文)

摘　　要：Compacted sand-bentonite mixtures are used as waste containment barriers(e.g.landfill liners and bentonite buffers for nuclear waste)to restrict contaminant transport.The potential for enhanced chemical containment of compacted sand-bentonite mixtures due to semipermeable membrane behavior has also been demonstrated.However,the extent to which membrane behavior persists in the presence of highly concentrated chemical solutions,which have been shown to degrade membrane behavior in bentonite-based barriers,remains largely unknown.Moreover,the limiting(threshold)salt concentrations at which membrane behavior of compacted sand-bentonite mixtures is effectively destroyed have not been evaluated.Accordingly,this study quantified the limiting membrane behavior of two duplicated specimens of compacted sand-bentonite mixture comprising 15%sodium bentonite(by dry mass)by determining the limiting salt concentrations at which measurable membrane behavior was eliminated.The specimens were exposed to increasingly higher source concentrations,Cot,of boundary monovalent salt solutions(KCl and NaCl)until measured values of the membrane efficiency coefficient,ω,were effectively zero.Overall,ωdecreased from an average of 0.032 to zero as Cot increased from 160 mmol/L KCl to 3.27 mol/L NaCl,resulting in limiting threshold salt concentrations for the two tests between 1.63 mol/L and 3.27 mol/L NaCl,which are significantly higher than those at which measurable membrane behavior has previously been demonstrated.

关 键 词：Chemico-osmosis Engineered barrier Sand-bentonite mixture Semipermeable membrane behavior Solute restriction Waste containment 

分 类 号：TU443[建筑科学—岩土工程] TU411[建筑科学—土工工程]