级配特性对砂土渗透系数影响试验研究

为深入分析级配特性对砂土渗透性的影响规律，采用常水头试验方法，研究了砂土不均匀系数、曲率系数、平均粒径和孔隙比对渗透系数的影响。采用正交试验方法对各影响因素进行了显著性分析，通过控制变量法进一步研究了各因素与渗透系数的关系。研究结果表明:渗透系数随曲率系数增大而增大，随不均匀系数的增大而减小，当不均匀系数增大到一定值（如本文中不均匀系数为11）时，渗透系数趋于稳定；渗透系数与平均粒径的变化关系接近线性正相关，在平均粒径不断增大的情况下，其渗透系数的变化幅度可达2个数量级。 

Experimental Study on Influence of Particle-Size Distribution on Permeability Coefficient of Sand

In order to investigate the influence of particle-size distribution on permeability of sand, the influence of uniformity coefficient, gradation coefficient, mean diameter, and void ratio on permeability coefficient was studied by constant head test. The significance of the influencing factors was then analyzed using orthogonal experimental design, and the relationships between the factors and the permeability coefficient were discussed by control variable method. The experimental results show that the permeability coefficient increases with the increase of gradation coefficient, and decreases with the uniformity coefficient. When the uniformity coefficient increases up to a certain value, the permeability coefficient tends to be stable (e.g.Cu=11 in this study). There is a nearly linear, positive correlation between permeability coefficient and mean diameter. With the increase of the mean diameter, the increasing amplitude of permeability coefficient can be up to two orders of magnitude.