湿度和密度双变化条件下的非饱和黄土渗透函数

准确确定非饱和土的渗透系数非常重要,而湿度和密度均会对非饱和土的渗透系数产生较为复杂的影响,因此对于对水敏感的非饱和黄土,如何将湿度和密度的影响综合引入渗透函数中,就值得深入研究。基于此认识,利用非饱和土水气运动联合测试方法,对1.4~1.67g/cm3之间几种干密度的非饱和黄土试样进行不同增湿级数的浸水渗透试验,结果表明试样在一定干密度范围内,增湿级数对其渗水系数测定值的影响较小,最大测定值与最小测定值的差值在2倍左右。在此基础上,将不同干密度下渗透系数比与饱和度的关系曲线进行分析,提出了考虑湿度和密度的渗透函数,并通过试验验证了该函数在一定条件下的合理性。

Saturation-density dependent permeability function for unsaturated loess

The coefficient of permeability for unsaturated soil is a key parameter in performing seepage analyses on saturated/unsaturated soil. The permeability coefficient of a saturated soil is a function of bulk density, while for unsaturated soils, it is a function of the degree of saturation provided a constant bulk density.However, the bulk density of soil is usually not constant. Both the degree of saturation and the bulk density influence the coefficient of permeability of certain unsaturated soil. Based on the above viewpoints, a series of unsaturated permeability tests are carried out under different infiltration paths and dry bulk densities. The relative permeabilities are normalized under different bulk densities to determine the normalized permeability function subject to bulk density variation. Furthermore, a new test is carried out to verify the proposed normalized permeability function. The predicted curves are in good accordance with the experimental data.