Drained Sand Behavior in Axisymmetric Tests at High Pressures

Abstract

The results of an experimental study of granular materials at high pressures are presented. Axisymmetric specimens of dense Cambria sand were tested in drained triaxial compression tests between confining pressures of 0.05 and 52 MPa. Drained triaxial extension tests between confining pressures of 0.25 and 52 MPa were also performed. As the confining pressure is increased, it was found that the stress-strain curve, and volumetric and axial strains to failure rapidly increased at a certain stress magnitude. This was shown to be directly related to a rapid increase in particle crushing. Beyond a certain higher value of stress magnitude, the stress-strain curves steepen, and the volumetric and axial strains to failure decrease. This was also shown to be directly related to the cessation of particle crushing and is typified by a zero rate of volume change at failure. The Mohr-Coulomb secant friction angle was found to be related to the rate of volume change at failure, whether the soil was dilatant or highly contractive and subject to large amounts of particle crushing.