Study on particle flow mesoscopic evolution law of coal gangue in compaction process

Abstract

It is of great significance to improve effect of solid filling by investigating the micro-evolution law of coal gangue filling materials in compaction deformation process. In this study, with taking particle breakage during compaction into account, particle flow numerical software PFC2D was used to construct a coal gangue particle model using flexible cluster model. Micro-evolution characteristics of particle systems with different ratios under uniaxial confined compression were analyzed. Meanwhile, relationship between coordination number, contact force and micro-characteristics of particles was studied. Results show that the stress-strain and fracture mode of simulation model are in good agreement with experimental results. Distribution of force chains and cracks evolution in the model particles were analyzed. It is found that most of the force chains are concentrated near larger particle units, forming a "skeleton force chain" phenomenon. Meanwhile, cracks mainly occurred around larger particle units. This phenomenon could result in the number of coordination numbers and contact force around large particle unit being larger than those of other particles.