A REVIEW ON THE PACKING DENSITY AND HOMOGENEITY OF GRANULAR MATERIALS

Granular materials are widely used in both industrial and engineering fields, where the quality of products and projects are highly dependent on the packing density and homogeneity of the granular materials. In this paper, previous studies conducted by domestic and overseas scholars on the packing density and homogeneity of granular materials are carefully reviewed and summarized. Results in the literature indicate that the packing density are related to the particle properties(particle size, shape and surface roughness, etc.),container properties(container size, shape and surface roughness, etc.),packing techniques(drop height, vibration condition, filling intensity and sequence, etc.),particle size ratio and distribution. The packing inhomogeneity(degree of segregation) increases with the increase of particle size difference, density difference and vibration acceleration, but decreases with the increase of size range, size class amount and vibration frequency, with indistinct susceptibility to particle shape. As for bentonite pellets used in high-level radioactive waste repository, it is worth devoting to improve the scientific and efficient in-situ packing techniques.