A Numerical Simulation of the Interaction of Aggregate and Rockfill in a Gangue Fluidized Filling Method

To solve the problem of gangue discharge in coal mining, fluidized gangue filling technology was developed. The key scientific problem of this technology is the diffusion characteristics of the gangue in the goaf. Therefore, a discrete element fluidized gangue model was established based on the ARR contact model. Based on the Rblock module, a goaf model with a certain void ratio was created, and the meso-parameters of fluidized gangue were calibrated. The fluidized gangue diffusion and rock displacement laws were explored under different grouting speeds, void ratios, and gangue particle sizes. The research results show that with the increase in the grouting speed and void ratio, and the decrease in the gangue particle size, the diffusion radius gradually increases, and the rock displacement in the goaf also gradually increases. Under given geological conditions, the total grouting mass of a single hole can reach 5.63 × 104 kg.