Pressure sensitivity of cemented granular materials

Abstract

Abstract In this paper, we explore the mechanical contact interaction of two identical elastic spheres uniformly coated with thin layers of a different elastic material. These two coating layers intersect over a finite contact area thus bonding the spheres. The normal contact stiffness and the shear contact stiffness increase when the spheres are axially pressed together, due to the increasing contact area. The dependence of these stiffnesses on the axial load is calculated by using a new approximate analytical solution. The solution also gives the distributions of the normal and shear stress components on the cemented contact. We use this solution to calculate the pressure dependence of the effective elastic moduli of a random pack of identical cemented spheres. This pressure dependence may be large if the initial contact radius is small. It is insignificant for large contact radii. If the spheres are in direct contact and the initial contact radius is small, the elastic properties of the cement have little effect on the pack's elastic moduli. However, if the spheres are separated by even a small cemented gap, the elastic properties of the cement may have a considerable effect on the pack's elastic moduli.