Experimental Study of Stick-Slip Behaviour of Dry Granular Materials

The stick-slip characteristics of glass beads were analysed based on an indoor triaxial test to investigate the mechanism of shallow vibration. Glass beads with diameters of 0.6–0.8 mm were used to conduct consolidated and undrained triaxial tests under cell pressures of 30, 60, 100, 200, 400, and 600 kPa at an axial strain rate of 0.02 mm/min. The results show that the deviator drop and the interval strain between the maximum deviator drops increase with cell pressure. In addition to the first compaction, the volumetric strain drops in the volumetric curve are related to the stick-slip. Under confining stresses of 30, 60, and 100 kPa, a large number of sharp and narrow peaks and valleys appear in the curve of cell pressure versus strain. Only sharp and narrow valleys are observed under confining stresses of 200, 400, and 600 kPa. It is found that static friction and sliding friction affect the stick-slip characteristics of the glass beads by observing the surface of the glass beads before and after the triaxial compression test. Finally, the continuous deformation and destruction of the force chain between the glass beads are the causes of stick-slip in the glass beads.