Soil-water characteristics and permeability of compacted loess considering effects of dry density

In order to investigate the influences of dry density on the soil-water characteristics and permeability of compacted loess, a one-dimensional instantaneous soil column infiltration instrument is used to carry out the constant head infiltration tests on the compacted loess with different dry densities, and the time-history curves of infiltration volume, volumetric water content and suction and the soil-water characteristic curves at the monitoring section are obtained. The unsaturated permeability coefficient is calculated by the transient profile method, and the relationship curves among permeability coefficient, suction and saturation are drawn respectively. The research results show that as the dry density increases, the time-history curves of infiltration tend to be flat, the turning point curves of the time-history of suction and volumetric water content move back, and the slope of the steep change section increases. Five time periods can be used to describe the change law. After the water flow from the bottom of the soil column is stable, the samples are not fully saturated, and the saturation increases with the dry density. As the dry density increases, the soil-water characteristic curve moves upward as a whole, and the function curves of permeability coefficient move downward as a whole. Based on the test results, the normalized models for the soil-water characteristic and permeability curves that directly consider the influences of dry density are established respectively.