Stick-slip mechanism in a granular medium

The article describes experimental data on an unsteady slip of granular materials under soft shear loading. The common features are established between the obtained discontinuous slip of a granular material and the “stick-slip” model of solid bodies with a rigid contact. The mechanism is specified by reduction in the dry friction force during transition from the rest state to a slip. The author found the area of the shear-force drop depending on the particle slip velocity for quarts sand. The process refers to a slow-motion class and is an intermediate stage in transition from very slow to faster motion.