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| Titel |
Partially saturated granular column collapse |
| VerfasserIn |
Barbara Turnbull, Chris Johnson |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250152612
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| Publikation (Nr.) |
 EGU/EGU2017-17468.pdf |
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| Zusammenfassung |
| Debris flows are gravity-driven sub-aerial mass movements containing water, sediments, soil
and rocks. These elements lead to characteristics common to dry granular media
(e.g. levee formation) and viscous gravity currents (viscous fingering and surge
instabilities). The importance of pore fluid in these flows is widely recognised, but there is
significant debate over the mechanisms of build up and dissipation of pore fluid pressure
within debris flows, and the resultant effect this has on dilation and mobility of
the grains. Here we specifically consider the effects of the liquid surface in the
flow.
We start with a simple experiment constituting a classical axisymmetric granular column
collapse, but with fluid filling the column up to a depth comparable to the depth of grains.
Thus, as the column collapses, capillary forces may be generated between the grains that
prevent dilation. We explore a parameter space to uncover the effects of fluid viscosity,
particle size, column size, aspect ratio, grain shape, saturation level, initial packing fraction
and significantly, the effects of fine sediments in suspension which can alter the capillary
interaction between wetted macroscopic grains. This work presents an initial scaling analysis
and attempts to relate the findings to current debris flow modelling approaches. |
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