密度对非饱和粘土渗透系数的影响研究

Influence of Density on Permeability Coefficient of Unsaturated Soil

取三峡库区某滑坡滑带土制备不同干密度的重塑土样进行饱和渗透试验和非饱和土水特征曲线试验,得到不同干密度重塑土样的土水特征曲线,通过理论公式预测出相应的非饱和渗透系数,进而得到不同干密度重塑土样渗透系数与基质吸力的关系。结果显示:渗透系数随着基质吸力的增大而呈非线性减小,当基质吸力较高时,渗透系数随基质吸力的变化比较小;当基质吸力较小时,渗透系数随基质吸力的变化比较大,而干密度对渗透系数的影响伴随整个试验过程进一步拟合分析得到非饱和渗透系数与干密度关系的函数表达式,并验证了表达式的合理性。

Taking the soil from a landslide in Three Gorges Reservoir as a sample,experiments on the seepage of saturated soil and on the unsaturated soil-water character curve are done with different density of samples.Then permeability coefficients of unsaturated soils are deduced by the formula from soil-water character curve.And the relationship between permeability coefficients of samples with different densities and suction are gotten.The result shows that permeability coefficient decreases with suction increase nonlinearly.It is found that matrix suction has more effect on the permeability coefficient in the low matrix suction than in the high matrix suction.However,the effect of densities on the permeability coefficient exists along with the whole experiment process.And the relation between unsaturated permeability coefficient and density can be fitted with certain function model.