An Update of Robert M. Koerner’s Models for the Packing Densities of Sands Using Image-Based Intrinsic Soil Properties

An update to Robert M. Koerner’s 1969 equations for minimum and maximum dry density of soils, based on intrinsic soil properties, is presented. The original equations used coefficient of uniformity (C_u), 10% by weight particle size (D₁₀) and particle sphericity defined by the ratio of projected particle area to the area of the smallest circumscribing circle. The updated equations are written for maximum and minimum void ratio. They utilize C_u, Wadell particle roundness (R) and sphericity (S) now defined as the ratio of particle width to length. The R and S values for sands, glass spheres, crushed aggregate and rice spanned a wide range of sizes and shapes. Computational geometry was used to obtain the R and S values from images of three-dimensional particle assemblies. The paper also discusses the developed image analysis methods and the significance of intrinsic soil properties to soil-geotextile, soil-geomembrane and soil-geogrid interface behavior.