The water storage capability and hydraulic conductivity of different expansive soils

For the strong and medium expansive soils of the middle-route of South-to-North Water Transfer Project, pressure plate tests and double-ring infiltration tests were carried out. The water storage capability, its influence factors and the evolution of hydraulic conductivity was comparative studied on different expansive soils. The results show, the soil with stronger expansion potential, higher fine grain content and higher dry density has better water retention capability. Saturated permeability coefficient of strong expansive soil is low, and it decreases with the increase of dry density. Unsaturated hydraulic conductivity, which has power function relationship with matrix suction, decreases with the decrease of the moisture content.