Behavior of coarse-grained soils under high stresses

Abstract

This is a report on an experimental investigation of the volume change and shearing behavior of a weathered subrounded quartzite sand. The results indicated that the coarse sands are crushed more easily than fine and medium sands under high confining pressures; they also indicated that shearing would cause greater changes in gradation in a sample than the application of isotropic stresses. Due to the large magnitude of particle crushing, coarse sand mobilizes strength at a slower rate than fine and medium sands. However, when sufficient degradation has occurred at large axial strains, the strengths of all 4 fractions are almost the same, regardless of their initial differences in porosity, particle size, and particle strength. The importance of particle crushing under high confining pressure is stressed in examining the volume change and shearing behavior of sands, namely, the stress-strain relationship, mode of failure, dilatancy rate, coefficient of earth pressure at rest, and effective stress ratio at failure. (Longer abstract available)