The triggering and propagation mechanisms of particle material avalanche constitute an exceedingly complex issue, with the crucial factor being the variation in the packing structure of the internal static accumulation area. To delve further into the packing structure of the rearrangement region within the avalanche system, this study employed an image-based approach to identify the spatial coordinates of three-dimensional cylindrical particles on the side and utilized Voronoi diagrams to characterize their packing structure. The results indicate that the Voronoi polygon area of the side-stacked particles follows a gamma distribution. Linear structures are more prone to participating in particle rearrangement, and they exhibit greater fragility in the direction perpendicular to the radius of the cylinder. During the avalanche interval, the changes in the scale of the passive layer particle packing structure are positively linearly correlated with the magnitude of the next avalanche and negatively linearly correlated with the time interval until the next avalanche occurs.