EFECT OF INDUCED SEEPAGE FLOW ON PERMEABLE SAND BED INSTABILITY

Abstract

We analyzed the effect of permeability of fluvial bedon the sandbed instability. The pressure gradient accompanied by the initial formation of sand waves inevitably produces the seepage flow through the fluvial bed. The induced seepage flow has significant effecton flowand sediment transport process. Bed load transport process is indirectly affected by the change of flow resistance, and is directly affected by seepage flow itself. Particularly, dislodgement of sand particles is severely influenced by the suction and injection. Hence, the induced seepage flow prompts or reduces the non-equilibrium bed load transport process and sand bed instability according to the permeability of bed materials particles and surface flow conditions. We applied stochastic sediment transport model in consideration of seepage effect, and revealed its effect permeable sandbed instability by comparing sandbed instability without permeability with that with permeability.