关键词: 渗透系数, 级配, 密实度, 孔隙尺寸, 粗粒土, 随机抽样组合

Abstract: Based on the plane pore-size and soil gradation in limited particle packing configuration, we adopt equiprobable random sampling to obtain several pore diameter percentage composition, and furthermore obtain the pore diameter accumulative distribution curves, the CSD-D and CSD-L, under the densest and loosest state of soil. Therefore, the actual pore diameter accumulative distribution curve CSD-R is worked out by using linear interpolation of soil relative density, so was the mean pore size . Finally, an empirical formula between permeability coefficient K and is established by plenty of permeability tests. The research indicates that the CSD-R curve considers the influence of particle gradation and density on pore size distribution simultaneously. The empirical formula is in agreement with the seepage law of porous medium theory that the permeability coefficient and the pore-size have a quadratic positive correlation. Compared with the test permeability coefficient of some coarse grained soil samples, the calculated value has a high accuracy, which is applicable to coarse grained soil whose uniformity coefficient Cuis less than 7 and effective diameter d10 is less than 9.6mm.

Key words: permeability coefficient, gradation, density, pore size, coarse grained soil, equiprobable random sampling