The Effects Of Modeling Particle Morphology And Gradation On The Numerical Simulation Of Three-Dimensional Particle Flow In Rockfill Granule Crushing

Using PFC^3Das a tool,a number of rigid single particles are bound to an irregularly shaped cluster of particles by means of parallel bond keys,which are used to simulate rockfill aggregates that can be broken aggregates.The crushing evolution process of coarse aggregate under load was discussed.The effects of cluster particle morphology,particle-level paired stress-strain characteristics and particle breakage were investigated.The results show:（1）With the change of axial stress,the evolution of particle crushing is divided into three stages:slow growth period in the initial stage of loading,rapid crushing stage in the middle stage of loading,and three stages of gradually stable period in the late stage of loading;The position of particle crushing gradually expands from the shear zone to the outside of the shear zone,indicating that the crushing of particles is a process from inside to outside.（2）Compared with the results of indoor triaxial tests,the results of numerical simulations of clusters of different shapes show different differences.The differences in cluster particle morphology affect the particle breakage and mechanical properties of the test samples.The higher the complexity,the lower the roundness of the cluster particles,has a better mechanical occlusion,so the ability to resist rotation is stronger;With the increase in the complexity of the cluster particle morphology,the particle breakage rate has increased.（3）In the cluster particle morphology,the change of particle size ratio has a certain impact on the particle breakage rate and numerical simulation effect.With the increase of particle size ratio,the particle breakage rate increases obviously,and the shear peak strength and residual strength decrease.（4）The elastic modulus,peak strength,and residual strength after shearing of the particle-matched rockfill material have important influences on the improvement of the non-uniform coefficient,better gradation,and dense aggregates,and the mechanical properties of the test sample are improved;Different particle size ranges The influence of the macroscopic mechanical properties of the test sample is different.The large particle size range plays a role of skeleton support in the soil structure.When this part of the particle size range is missing,the peak strength and elastic modulus of the test sample are directly affected.（5）The particle size distribution of the rockfill particles has a certain impact,the aggregate level is poor,the particle filling capacity between the cluster particles and the cluster particles is reduced,the contact force transmission ability is poor,the stress concentration is obvious,and the particle breakage rate is high;The particle crushing has priority,under the same stress conditions,the large particle size of the first crushing,after the small particle size crushing.