Hydraulic conductivity of aqueous bentonite suspensions

Abstract

In many circumstances, filtration of two-phase, solid-liquid systems can be described by theory based on Darcy's Law and an appropriate continuity equation. The theory requires that relations between the water content and (a) the water potential, and (b) the permeability are well defined. This paper describes experiments which permit calculation of both these relations in a water-bentonite suspension. The permeability function calculated directly from steady state experiments compares with that calculated indirectly from transient experiments, thus confirming the basic assumptions of the theory. It is shown that both the water content-water potential, and the water content-permeability relations are sensitive to solution salt concentration. However, the water potential-permeability relation is nearly independent of salt concentration, thus allowing considerable simplification in the information sufficient and necessary to characterize this system.