Influence of strain rate on dilatancy and strength of Oshima granite under uniaxial compression

Abstract

Uniaxial compression tests have been conducted on Oshima granite under various constant axial strain rates ranging from 10−8 to 10−4. The results showed that the strength and the acoustic emission rate increased exponentially with increasing strain rate. The inelastic volumetric strain rate defined by the differentiation with respect to the stress increased with decreasing strain rate. The redistribution of microcracks due to subcritical crack growth was considered theoretically, and the equations derived from the theory were compared with the experimental results. The agreement between the theoretical and experimental results shows that stress corrosion plays not only a major role in the brittle creep under constant load but also dominates the strain rate effects on strength and dilatancy observed in the constant strain rate loadings.