Energy Dissipation of Debris Flows over Stepped Gradients and Erodible Beds in Open Channel

Abstract

Energy of debris flows in steep mountainous channels is mostly consumed by erosion, collision, and hydraulic jumps due to abrupt topographic changes. In this study, flume experiments were performed to study the energy dissipation of debris flows over stepped gradients and erodible beds. A power law relationship between the depth-averaged velocity and flow depth was used to calculate the kinetic energy of debris flows. The experimental data indicate that the energy loss of entrainment per unit volume of bed sediment has an approximately linear relationship with transition angle and porosity. The net resistance coefficient also demonstrates more energy dissipation when debris flows move downward on slopes with a greater gradient change.