The exploration of force chains in bonded granular materials: A numerical study

Abstract

The bonded particles in DEM simulations have been widely used to reproduce the rock behaviour. Inside the DEM model, forces are transmitted through contacts between particles. It has been found that some chain-like particle groups called 'force chains' bear the majority of applied loads in non-cohesive granular materials. It can be supposed that there are also similar chain structures in bonded granular materials, which could be helpful to understand the relationship between the grain-scale structure and macroscopic properties. The aim of this paper is to explore the force chains or similar chain-like structures in bonded granular materials. Several models were generated representing different structures, such as models comprised of polydisperse particles, and models after random deletion and selective deletion of particles. Then, uniaxial compressive tests were conducted on these numerical models. The simulation results indicate that there are also chain structures in bonded granular materials and models after deleting particles with large principal stresses have the smallest peak stresses while models in the control group have the same porosity. This verifies that these particles are important for the model stability under external loads. At last, an algorithm was found suitable to extract force chains and the connectivity of force chains was discussed and analysed.