Theoretical assessment of fabric and permeability changes in clays affected by organic contaminants

摘要: Permeability of clay is known, from laboratory tests, to increase over four orders magnitude during low effective stress permeation with some concentrated organic liquids. On an engineering scale, in a one-dimensional purely advective flow through finite layer, such evolution shown numerically cause substantial acceleration the progress contamination front, compared constant permeability case. For 100-fold intrinsic for 100% replacement pore water organic, two times shorter transit time predicted. A series quantitative fabric models based on interpretations and concepts proposed past are reformulated terms. These associated adsorbed withdrawal, particle migration, deposition leading clogging, changes connectivity or flocculation. derived simplified structure formed by dominant pores actual size distribution. The formulation applied interpret previously published experimental data. It found that connection must be postulated rather than parallel one, smaller acting as bottle neck. simple enlargement model not realistic. most consistent results obtained flocculation involving rotation generating wedge-shaped channels. Resume : sait, sur la base d'essais de laboratoire, que permeabilite d'une argile peut etre augmentee quatre ordres grandeur pendant permeation, certains liquides organiques concentres sous contraintes effectives basses. l'echelle l'ingenieur, si considere un ecoulement unidimensionnel purement advectif travers une couche d'epaisseur finie, montrer numeriquement qu'une telle substantielle l'avancee du front contamination, compare au cas constante. Pour augmentation intrinseque 100 fois avec