Abstract：Based on an engineering example, PFC discrete element simulation was applied to realize arch formation by changing parameters. The formation and propagation rules of overpressure and elastic wave of silo wall were systematically analyzed when silo grain was discharged into arch. The results indicate that the warehouse wall appears overpressure when the grain is discharged into an arch, due to the reduction of particle discharge velocity. As the height of silo increases, the side pressure of silo wall decreases when grain is discharged into arch, the increment of overpressure decreases, and the overpressure coefficient increases at each depth The overpressure wave peaks appear successively with the increase of height, indicating that the overpressure starts from the arch foot and spreads upward in the form of waves on the wall of the warehouse. Through the analysis of the simulation results, it is found that the time interval of the fluctuation is even at all depths of the silo. The formation mechanism of overpressure of warehouse wall under arch-forming condition is revealed.

Keywords：grain arched; overpressure on silo wall; elastic overpressure fluctuation; PFC discrete element simulation.