Characteristics of a Debris-Flow Drainage Channel with a Step-Pool Configuration

Abstract

Theoretical analysis and experimental testing of a debris-flow drainage channel with a step-pool configuration are conducted in this paper. The design conditions of the drainage channel with step-pool configuration were obtained by theoretical analysis, including the design shape of the step-pool configuration, design slope of the step section, and total length of a single step-pool configuration. In addition, the correction coefficients of the debris-flow jet length were obtained with different debris-flow densities by comparing the experimental and calculation results. Moreover, the debris flow repeats an acceleration-deceleration motion in the drainage channel to achieve a balanced discharge without scouring or deposition. At the downstream of the step-pool configuration, the average debris-flow velocity decreased by approximately 28 and 40% with debris-flow densities of ρ=1,700 and 2,000 kg/m3. Furthermore, the energy-dissipation ratio varied between debris-flow densities of ρ=1,700 and 2,000 kg/m3. Finally, the authors discuss different types of drainage channels in practical debris-flow hazard-mitigation engineering and parameter variations of these drainage channels.