Thresholds in the sliding resistance of simulated basal ice
We report laboratory determinations of the shear resistance to sliding melting ice with entrained particles over a hard, impermeable surface. With higher particle concentrations and larger particle sizes, Coulomb friction at particle-bed contacts dominates and the shear stress increases linearly wit...
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Copernicus Publications
2007
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fttriple:oai:gotriple.eu:oai:doaj.org/article:12e667ca450b4d799d8ade7ff8fe3be4 2023-05-15T18:32:13+02:00 Thresholds in the sliding resistance of simulated basal ice L. F. Emerson A. W. Rempel 2007-10-01 http://www.the-cryosphere.net/1/11/2007/tc-1-11-2007.pdf https://doaj.org/article/12e667ca450b4d799d8ade7ff8fe3be4 en eng Copernicus Publications 1994-0416 1994-0424 http://www.the-cryosphere.net/1/11/2007/tc-1-11-2007.pdf https://doaj.org/article/12e667ca450b4d799d8ade7ff8fe3be4 undefined The Cryosphere, Vol 1, Iss 1, Pp 11-19 (2007) geo envir Journal Article https://vocabularies.coar-repositories.org/resource_types/c_6501/ 2007 fttriple 2023-01-22T18:47:36Z We report laboratory determinations of the shear resistance to sliding melting ice with entrained particles over a hard, impermeable surface. With higher particle concentrations and larger particle sizes, Coulomb friction at particle-bed contacts dominates and the shear stress increases linearly with normal load. We term this the sandy regime. When either particle concentration or particle size is reduced below a threshold, the dependence of shear resistance on normal load is no longer statistically significant. We term this regime slippery. We use force and mass balance considerations to examine the flow of melt water beneath the simulated basal ice. At high particle concentrations, the transition from sandy to slippery behavior occurs when the particle size is comparable to the thickness of the melt film that separates the sliding ice from its bed. For larger particle sizes, a transition from sandy to slippery behavior occurs when the particle concentration drops sufficiently that the normal load is no longer transferred completely to the particle-bed contacts. We estimate that the melt films separating the particles from the ice are approximately 0.1 µm thick at this transition. Our laboratory results suggest the potential for abrupt transitions in the shear resistance beneath hard-bedded glaciers with changes in either the thickness of melt layers or the particle loading. Article in Journal/Newspaper The Cryosphere Unknown |
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English |
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geo envir L. F. Emerson A. W. Rempel Thresholds in the sliding resistance of simulated basal ice |
topic_facet |
geo envir |
description |
We report laboratory determinations of the shear resistance to sliding melting ice with entrained particles over a hard, impermeable surface. With higher particle concentrations and larger particle sizes, Coulomb friction at particle-bed contacts dominates and the shear stress increases linearly with normal load. We term this the sandy regime. When either particle concentration or particle size is reduced below a threshold, the dependence of shear resistance on normal load is no longer statistically significant. We term this regime slippery. We use force and mass balance considerations to examine the flow of melt water beneath the simulated basal ice. At high particle concentrations, the transition from sandy to slippery behavior occurs when the particle size is comparable to the thickness of the melt film that separates the sliding ice from its bed. For larger particle sizes, a transition from sandy to slippery behavior occurs when the particle concentration drops sufficiently that the normal load is no longer transferred completely to the particle-bed contacts. We estimate that the melt films separating the particles from the ice are approximately 0.1 µm thick at this transition. Our laboratory results suggest the potential for abrupt transitions in the shear resistance beneath hard-bedded glaciers with changes in either the thickness of melt layers or the particle loading. |
format |
Article in Journal/Newspaper |
author |
L. F. Emerson A. W. Rempel |
author_facet |
L. F. Emerson A. W. Rempel |
author_sort |
L. F. Emerson |
title |
Thresholds in the sliding resistance of simulated basal ice |
title_short |
Thresholds in the sliding resistance of simulated basal ice |
title_full |
Thresholds in the sliding resistance of simulated basal ice |
title_fullStr |
Thresholds in the sliding resistance of simulated basal ice |
title_full_unstemmed |
Thresholds in the sliding resistance of simulated basal ice |
title_sort |
thresholds in the sliding resistance of simulated basal ice |
publisher |
Copernicus Publications |
publishDate |
2007 |
url |
http://www.the-cryosphere.net/1/11/2007/tc-1-11-2007.pdf https://doaj.org/article/12e667ca450b4d799d8ade7ff8fe3be4 |
genre |
The Cryosphere |
genre_facet |
The Cryosphere |
op_source |
The Cryosphere, Vol 1, Iss 1, Pp 11-19 (2007) |
op_relation |
1994-0416 1994-0424 http://www.the-cryosphere.net/1/11/2007/tc-1-11-2007.pdf https://doaj.org/article/12e667ca450b4d799d8ade7ff8fe3be4 |
op_rights |
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1766216306301861888 |