Contributed Papers

Acta Mechanica

, Volume 63, Issue 1, pp 161-178

First online:

Large debris flows: A macro-viscous phenomenon

  • T. R. H. DaviesAffiliated withDepartment of Agricultural Engineering, Lincoln College, University of Canterbury

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Field observations from a variety of sources suggest that destructive debris flows occur when the density of the fluid-solid mixture exceeds about 1.5 T/m3, and that their destructive ability is due to their pulsing nature and to their ability to carry large boulders.

If debris flows are treated as a macroviscous flow of large stones in a slurry of fine solids in water, several of their obvious characteristics (boulder transport, deep bed erosion, intermittent jamming) can be explained. Further, the amplification and translation in a main channel of random surges due to jamming in tributaries explains the regular, large pulses in Chinese debris flows as a roll-wave phenomenon.