Experimental and numerical analysis of stick-slip instability of granular materials

Abstract

The paper presents a comparison between experimental observations of stick-slip behaviours of glass beads reproduced in laboratory and numerical simulation obtained by two-dimensional discrete element model able to reproduce the stick-slip dynamics. A triaxial experimental set-up has been used to investigate the stick-slip response of granular matter under quasi-static loading. On the other hand the Particle Flow Code (PFC2D) has been used in this article that performs numerical simulation of stick-slip behaviour of granular matter. The model is used to simulate biaxial compression experiment on dry specimen of glass beads. Once the results are well in agreement with laboratory data, a parametric study is performed to investigate the evolution of the model’s behaviour due to varying parameters such as vertical strain rate, coefficient of friction and particle stiffness. The results show an increase in critical state strength in the models with higher vertical strain rate, bigger coefficient of friction and higher particle stiffness. A new algorithm is developed to record the sliding work and sliding velocity induced by seismic events in the sample.