Experimental and numerical study of stick-slip phenomenon in granular materials.

The stick-slip is a characteristic phenomenon of various mechanical systems, occurring when two bodies slide relative to each other. Friction plays a dominant role in this phenomenon, transitioning from static to dynamic when sudden movements take place. Studying this behaviour is particularly important for understanding stress transfer in granular materials. The study examines the development of the stick-slip phenomenon under plane strain conditions, which are commonly encountered in large-scale geotechnical structures. Experiments performed on glass bead samples investigate the effects of varying confining pressures, shear rates, initial void ratios, and degrees of bead wear on the development and characteristics of the stick-slip phenomenon. Additionally, a plane strain triaxial test is simulated using the discrete element method (DEM). Although the stick-slip events are not fully reproduced, some micro-slips are identified in the results. The physical mechanism underlying their development appears to correspond to the standard stick-slip behaviour reported in the experiments. Since micro-mechanical behaviour is a key to understanding the stick-slip phenomenon, incorporating DEM analyses opens a new route for determining micro-parameters and linking them to macro behaviour.