Mixing simulation of cohesive particles in a soil mixer

Soil particle mixing is an important research hotspot in the emerging field of waste soil resources. In this study, the discrete element method (DEM) is used to characterize the mixing of cohesive particles in a soil mixer. To verify the mixing effect of this mixer on cohesive materials, the forces between the particles are simulated using a cohesive contact model. The effects of filling level, rotating shaft speed and size, particle cohesion and size on particle dynamics and mixing performance within the mixer are investigated. The mixing process of the particles is analyzed to quantify the mixing performance by using the coordination number (CN), average velocity, contact force network and mixing index. To assess the degree of mixing using the Lacey mixing index, a grid system is used to divide the mixing area so that the mixing index can be calculated. The results show that this mixer is suitable for mixing cohesive particles and that a lower filling level leads to better mixing efficiency. In addition, the mixing efficiency is significantly improved as the speed and size of the rotating shaft in the mixer increased.