Author(s): Hsien-Ter Chou; Ching-Fang Lee; Yi-Hong Tu; Su-Chin Chen
Linked Author(s): Su-Chin Chen
Keywords: Debris flow; Seepage flow; Runoff; Granular pile; Bagnold’s rheology
Abstract: The mobilization process of a granular pile and the associated debris flow by the action of upstream runoff and seepage was experimentally investigated in an inclined flume. The critical condition and the failure process of the granular pile were analyzed by employing the PTV approach. The effect of runoff discharge, flume slope and permeability are explored. During the mobilization process, a partially unsaturated granular snout was formed, then became a bulge at the surge front just as stony debris flows in the field. The velocity profile in the unsaturated snout depicts a Bagnold’s rheology, but it deviatesslightly from Bagnold’s profile due to presence of bottom slipping in theintermediate saturated zone. In addition, the evolution of solid fraction indicates that the critical failure condition is controlled by the seepage flow. A dimensionless peak debris surge related to the chute slope is also presented.
Year: 2013