Experiment of Energy Dissipation and Energy Release during Stick-Slip within Glass Beads

The energy dissipation and energy release of fault gouge could be explained by analyzing the characteristics of stick-slip of glass beads. The glass beads of 0.6-0.8 mm were used to conduct the test from CVP company. The triaxial tests of dry and loose glass beads were carried out under the cell pressure of 30, 60, 100, 200, 400 and 600 kPa with axial strain rate of 0.02 mm/min. The energy dissipation and energy release in the process of failure are discussed with the axial strain rate of 10% in order to decrease the errors due to the rotation of principal stress. The results show that with increasing of cell pressure, the frequency of main shock decreases, the deviatoric stress drop increases, the ratio of deviatoric stress drop to maximum deviatoric stress becomes stable gradually. The volume of sample shrinks and acoustic emission appears in the moment of deviatoric stress drop. The energy controls the deformation and failure properties of the sample during stick-slip: the more the dissipation is, the less the frequency of sliding becomes. Stick-slip can be expressed as the process of energy dissipation and energy release. Finally, the three stages of sliding during stick-slip are discussed from the aspect of thermodynamics. The stick-slip motion is a combined effect of irreversible dissipated energy and releasable strain energy.