CALCULATION OF BED PROFILE VARIATIONS WITH SAND-GRAVEL MIXTURE IN A STEEP CHANNEL RESERVOIR BY MODIFYING TRACTIVE FORCE

抄録

The bed profile of sediment deposition in a reservoir with a sand-mixture is studied in a steep channel. Following the findings on experiments in a laboratory flume for the mixture of fine and coarse sediment, the deposition profile is numerically simulated. The one-dimensional continuity equations of flow and the sediment transport are applied to calculate the bed profile of the mixture corresponding to the water surface profile. Due to the minimum energy at the critical condition of flow, a sub-critical region below the jump and a super-critical section above the jump are formed. The deposition of sediment occurs in the sub-critical region, where the flow velocity decreases. The difference of mobility of each grain size is considered in the sand-gravel mixture, where the sediment sorting in the part of the sediment deposition is occurred. The modification factors are introduced on the transport mode of individual particles in the sand-gravel-mixture.