抄録
The main purpose of this study is to understand the evolution process of river bed in case that the sediment size distribution is extremely wide. In this fundamental experimental study, the bed is composed of three groups of sediment, and one of the grain size is completely different from each other. One is L-particle which cannot move at all in the stream, and constitutes a bed frame. And M-particle or S-particle exists in the space surrounded by L-particles, and moves as bed load or suspended load, respectively. Hiding effect of L-particle on M and S-particles was evaluated, and the vertical structure of bed was also made clear in the evolution process toward a static equilibrium state. In addition to these, it was found that the arrangement of L-particle cannot affect the state of equilibrium state.
