干密度对黄土渗透系数的影响

非饱和渗透系数是研究非饱和土入渗规律的重要参数,同时也是研究边坡失稳和地基浸湿变形的重要基础。本文采用变水头法测量原状黄土和重塑黄土饱和渗透系数,基于ChildsCollis-Geroge模型,结合土水特征曲线和饱和渗透系数,详细探讨了原状黄土、不同干密度非饱和重塑黄土体积含水率与渗透系数的关系和规律。结果表明,原状黄土的饱和渗透系数远小于重塑样,重塑土样饱和渗透系数随着干密度的增大而减小;黄土非饱和渗透系数减小趋势随着干密度增大而减小,但在残余含水率附近,不同干密度下试样的渗透性基本相同。

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.