Influence of debris flow discharge on equilibrium bed slope
Results obtained fromboth of flume data and theories suggest that equilibriumbed slope in debris flow over an erodible bed is determined uniquely by supplying sediment discharge rate when the movements of sediment particles are laminar and thus no suspended transportation take place. This means that the static yield stress dominates in debris flow and that sediment concentration is predicted by the balance of yield stress and external shear stress on the bed surface as described in our previous studies. On the other hand, if parts of sediment particles in debris flow body are transported in suspension, sediment concentration will be larger and the equilibrium bed slope will decrease. These facts are supported by Egashira et al.s flume data and others experimental data. In the present study, flume tests in the flowover erodible bed are conducted using uniformsediment particles, and if a part of debris flowbody is turbulent, influence of flow discharge on the hyper-concentrated flow is discussed using flume data such as velocity distributions and equilibrium bed slope. In addition, non-dimensional parameter, which is similar to Reynolds number, is proposed with Egashira et al.s constitutive equations of debris flows in order to analyze flow characteristics such as the thickness of sediment laminar flow layer.
phase transition debris flow flow scale equilibrium bed slope two layers model
T. Itoh S. Egashira
El Koei Co., Ltd, Japan NEWJEC Inc., Japan
国际会议
成都
英文
151-163
2007-05-17（万方平台首次上网日期，不代表论文的发表时间）