Abstract：Water diffusion ratio of unsaturated loess considering the influence of density is studied by test. The test data show that the variation of soil density，for loess with higher water content，can result in great change of diffusion ratio. For the loess with lower volumetric water content，the variation of soil density can result in less change of diffusion ratio. Furthermore，for loess samples with different densities，the matrix suction of the unsaturated loess with different volumetric water contents is tested. On the basis of analysis of test data，the relationship between water diffusion ratio and density of unsaturated loess is explored，and the specific water volume of loess is given. The formula is got to define the seepage coefficient of unsaturated loess considering the influence of density. After analyzing the change law of permeability coefficient resulting from the change of soil volumetric water content and density，it is pointed out that the permeability coefficient of the unsaturated dense loess is sensitive to soil density change compared with loose loess.
