Influence of dry density on coefficient of permeability of unsaturated loess

The unsaturated permeability coefficient is one of the important parameters in the researches on the rules of unsaturated soil infiltration and the important basis of the researches on the instability of slopes and humidification deformation of foundations. The variable water head method is used to measure the permeability coefficients of undisturbed soil and remolded saturated loess. Combined with the soil-water characteristic curve and the saturated permeability coefficient, based on the Childs & Collis-George model, remolded unsaturated loess with different dry densities and the relationships between coefficient of permeability and volumetric moisture content as well as the rules of undisturbed loess are discussed. The results show that the saturated coefficient of permeability of the remolded loess samples is greater than that of the undisturbed loess samples, and it decreases with the increase of the dry density. The unsaturated coefficient of permeability of loess coefficient decreases as the moisture content is reduced, and the decrease trend decreases as the dry density increases. However, under about the residual moisture content, the permeability of the samples with different dry densities is basically identical.