Energy aspects of particle breakage in drained shear of sands

The effect of particle breakage on the shear strength of sand is studied by considering the energy consumption due to particle breakage at the contacts between sand particles. A stress-dilatancy relationship for sand under a triaxial loading condition is developed, adopting Rowe's minimum energy ratio principle. Particle breakage and its relation to the shear strength of a sand can then be evaluated based on this relationship. The increment of specific surface of the sand is used as an indication of the amount of particle breakage. Results of laboratory triaxial compression tests for Fulung sand, Tamsui River sand and a decomposed granite are examined and compared with the stress-dilatancy relationship. The effect of particle breakage on the shear strength of a sand can be correlated with rate of energy consumption of particle breakage and rate of increment in particle surface area per unit volume of sand as proposed in this study. The rate of energy consumption by particle breakage increases,vith increasing confining pressure, but is only slightly affected by the relative density of sand. The effect of energy consumption of particle breakage on the friction angle of these sands is also evaluated.