A Model for Estimating the Hydraulic Conductivity of Granular Material Based on Grain Shape, Grain Size, and Porosity

A model for delineating the relative importance of particle size, particle shape, and porosity, (and their interactions), in explaining the variability of hydraulic conductivity of a granular porous medium is developed and tested. Three types of porous media are considered in this work: spherical glass beads; granular sand; and irregularly shaped, shredded glass particles. A reliable method for quantifying the three‐dimensional shape and packing of large samples of irregular particles based on their angle of repose is presented. The results of column experiments indicate that in the size range examined (i.e., 149 μm to 2380 μm), the single most important predictor of hydraulic conductivity is seen to be particle size, explaining 69% of the variability. Porous media comprising irregular particles exhibit lower hydraulic conductivity only for the larger (707 to 841 μm) particles. For the smaller (149 to 177 μm) particles, particle shape has no observable influence on hydraulic conductivity. The results of the regression analysis reveal the importance of the interaction between particle size and porosity, indicating that similar pore configurations for a given type of particle are not achieved at different sizes. This empirical model seems to provide better estimates of the hydraulic conductivity of granular porous media comprising irregular particles than selected models based solely on grain size, including Hazen, Kozeny‐Carman, and more recently Alyamani and Sen. Copyright © 1995, Wiley Blackwell. All rights reserved

Duke Scholars

Author J. Jeffrey Peirce Civil and Environmental Engineering