Effect of Bed Sediment Entrainment on Debris-Flow Resistance

Abstract

Entrainment of sediment from hillslope and channel usually has a significant influence on resistance of debris flow. This effect is studied by flume experiments of debris flow over rigid and erodible beds. Fifty contrast flume tests show that the flow resistance over the erodible bed is significantly larger than that over the rigid bed because of higher energy consumption resulting from sediment transport. A new formula of debris-flow resistance involving the entrainment effect is obtained from the erodible-bed data by nondimensional multiple regression analysis.