Pore-size evolution of a hydraulically deposited silty sand due to drying and rewetting

Abstract

This study investigates the effects of drying and rewetting on the pore size distribution in a silty sand. It is shown that drying reduces the void ratio and at the same time alters the pore size distribution although not with all sizes of pores reducing in volume. As the extent of drying increased the volume fraction of the larger pores increased while the volume fraction of the smaller pores decreased. Subsequent rewetting does not alter or reverse the pore rearrangement in a significant way. Inferred and directly measured soil-water characteristic curves are characterised using fractal theory. Increased drying increases the slopes of scanning curves and reduces air entry and air expulsion suctions. There is no significant change to the fractal dimension of the pore size distribution. In practice, the drying induced pore rearrangement could lead to a stability concern, especially for marginally stable soil deposits, as larger pores become greater in number, a change not erased by rewetting, likely making the soil more prone to collapse or liquefaction.