UNSATURATED FLOW MECHANISMS IN LOW-SWELLING CLAYS

Abstract

The present paper evaluates the unsaturated flow mechanisms in low-swelling clays by studying the effects of dry bulk density, temperature, initial water content, and inlet suction on such unsaturated flow aspects as wetting front advance and soil moisture profile. The soil moisture are plotted in a dimensionless form, and a statistical comparison. In general, the effects of the internal forces of interaction and hence the swelling potential are not appreciable. This is well supported by the linear relationship between wetting front advance and square root of time under practically all testing conditions, thus indicating a stable pore geometry during the flow process. In most cases a simple capillary model based upon the initial pore structure seems to be able to explain most of the observed phenomena. However, the change in the shape of the soil moisture profiles with changes in initial water content and inlet suction still cannot be fully accounted for. /Author/