LAUSR

This study posits that soil particles in the filter layer are ellipsoidal. The effective pore radius of the filter material was calculated for various particle-shape parameters and distributions. The relationship between the porosity of the filter material and the ratio of the long axis to the short axis of ellipsoidal particles in a loose arrangement was also examined. The results indicate that the porosity of the filter material initially decreases and subsequently increases with increases in the ratio of the long axis to the short axis; however, the rate of increase progressively slows. A method for transforming irregularly shaped particles into ellipsoidal forms is proposed. The particle-shape parameter, S, is introduced to characterize the shape of irregular particles. The relationship between particle-shape parameters and the ratio of the long axis to the short axis was investigated specifically for ellipsoidal particles. It was found that the particle-shape parameters exhibit an approximately linear relationship with the ratio of the long axis to the short axis within a specific range. The discrete element method was employed to investigate the impact of particle shape on the filtration characteristics of the filter layer and was complemented by comparative experimental analysis. By analyzing the pore structures of spherical and ellipsoidal particles, this study predicts the relationship between pore structure and particle-shape parameters for any irregularly shaped natural-particle filter layer.