Abstract
Heavily sediment-laden flows have been described and classified as hyperconcentrated sediment flows, including mud floods, mudflows, and debris flows. The authors prescribe definitions based on governing physical processes and limited concentrations of cohesive material. Viscous mudflows contain large concentrations of fine cohesive material. Rocky debris flows contain large concentrations of clastic material. Rheological analyses should recognize four types of shear stresses: 1) yield stress; 2) viscous stress; 3) turbulent stress; and 4) dispersive stress. These shear stresses combine into a quadratic rheological model. Dimensionless parameters from the ratio of shear stress terms identify the predominant physical process.
The two-dimensional model FLO-2D has been developed for the simulation of a wide range of hyperconcentrated sediment flows based on the quadratic rheological model. The simulation of the Pine Creek mudflow during the 1980 eruption of Mount St. Helens is presented as an example of our continuing progress in the physically-based analysis of natural disasters from heavily sediment-laden flows.
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© 1997 Springer-Verlag
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Julien, P.Y., O'Brien, J.S. (1997). Selected notes on debris flow dynamics. In: Armanini, A., Michiue, M. (eds) Recent Developments on Debris Flows. Lecture Notes in Earth Sciences, vol 64. Springer, Berlin, Heidelberg. https://doi.org/10.1007/BFb0117766
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DOI: https://doi.org/10.1007/BFb0117766
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