湿度和密度双变化条件下的非饱和黄土渗气渗水函数

饱和度和密度都会对非饱和土的渗透系数产生影响,而准确确定非饱和土的渗透系数在饱和/非饱和土体渗流分析中非常重要。利用改进的非饱和土水气运动联合测定仪,对重塑非饱和黄土试样进行不同增湿级数和初始干密度条件下的渗透试验,研究饱和度、干密度、渗气系数及渗水系数间的关系,建立湿度和密度双变化条件下的渗气渗水函数,并通过试验验证该函数的适用性和准确性。研究表明,该函数既可用于确定渗水系数,又可用于定量描述非饱和土孔隙中水气运动之间的相互影响,其在非饱和土固结分析、稳定分析及饱和非饱和渗流分析中具有较强的应用前景。

DENSITY-SATURATION-DEPENDENT AIR-WATER PERMEABILITY FUNCTION OF UNSATURATED LOESS

The coefficient of permeability of unsaturated soil is a key parameter in performing seepage analysis in saturated/unsaturated soils. However，both the degree of saturation and the dry density influence the coefficient of permeability of unsaturated soil. A series of experiments are performed by using the improved measurement apparatus under different infiltration steps and various initial dry densities of unsaturated remoulded loess specimens. According to the results，the relationships among degree of saturation，dry density，coefficients of air and water permeability are analyzed. A new density-saturation-dependent air-water permeability function is put forward based on the above relationships；and it can not only determine the coefficient of water permeability but also quantitatively describe the mutual influence of movement of both air and water in the void of unsaturated soil. Finally，the new experiment is provided to verify the proposed permeability function. It is shown that the predicted curves are in good accordance with the experimental data.