A NOVEL FORMULA FOR MIXED-GRAIN SEDIMENT DEPOSITION PROCESSES

Abstract

 While the active layer concept has been applied to sediment transport problems in mixed-grained river beds, the problems of porosity and exchange layer thickness remain unsolved. In this study, the Eulerian sediment deposition model is proposed, focusing on the fact that the active layer is not a problem in the Descrete Element Method that solves the motions of individual particles. First, based on the basic equations used for DEM and the available porosity on the riverbed deposition conditions of sediment particles, the equations for temporal variations in particles deposition heights and particles proportions were derived and compared with the conventional equations with the active layer concept. Sedimentation experiments were conducted under static conditions, and we found that the sedimentation process depend on the ratio of coarse to fine particles. The applicability of the Eulerian sediment deposition model to the sedimentation process of mixed-grained sediment was validated through comparisons with experimental results.