Iverson, Richard M. 1997. Hydraulic modeling of unsteady debris-flow surges with solid-fluid interactions. In: Chen, Cheng-lung, ed. Debris-flow hazards mitigation: mechanics, prediction, and assessment: Proceedings of first international conference; 1997 August 7-9; San Francisco, CA. New York, NY: American Society of Civil Engineers: 550-560.
Interactions of solid and fluid constituents produce the unique style of motion thattypifies debris flows. To simulate this motion, a new hydraulic model represents debrisflows as deforming masses of granular solids variably liquefied by viscous pore fluid. Themomentum equation of the model describes how internal and boundary forces change ascoarse-grained surge heads dominated by grain-contact friction grade into muddy debris-flow bodies more strongly influenced by fluid viscosity and pressure. Scaling analysisreveals that pore-pressure variations can cause flow resistance in surge heads to surpassthat in debris-flow bodies by orders of magnitude. Numerical solutions of the coupledmomentum and continuity equations provide good predictions of unsteady, nonuniformmotion of experimental debris flows from initiation through deposition.