Thresholds in the sliding resistance of simulated basal ice
International audience We report on 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 str...
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ftccsdartic:oai:HAL:hal-00298524v1 2023-05-15T18:32:09+02:00 Thresholds in the sliding resistance of simulated basal ice Emerson, L. F. Rempel, A. W. Department of Geological Sciences Oregon University of Oregon Eugene 2007-06-29 https://hal.archives-ouvertes.fr/hal-00298524 https://hal.archives-ouvertes.fr/hal-00298524/document https://hal.archives-ouvertes.fr/hal-00298524/file/tcd-1-99-2007.pdf en eng HAL CCSD Copernicus hal-00298524 https://hal.archives-ouvertes.fr/hal-00298524 https://hal.archives-ouvertes.fr/hal-00298524/document https://hal.archives-ouvertes.fr/hal-00298524/file/tcd-1-99-2007.pdf info:eu-repo/semantics/OpenAccess ISSN: 1994-0432 EISSN: 1994-0440 The Cryosphere Discussions https://hal.archives-ouvertes.fr/hal-00298524 The Cryosphere Discussions, Copernicus, 2007, 1 (1), pp.99-122 [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences info:eu-repo/semantics/article Journal articles 2007 ftccsdartic 2021-10-24T20:58:41Z International audience We report on 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 ?m 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 The Cryosphere Discussions Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
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Open Polar |
collection |
Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
op_collection_id |
ftccsdartic |
language |
English |
topic |
[SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
spellingShingle |
[SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences Emerson, L. F. Rempel, A. W. Thresholds in the sliding resistance of simulated basal ice |
topic_facet |
[SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
description |
International audience We report on 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 ?m 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. |
author2 |
Department of Geological Sciences Oregon University of Oregon Eugene |
format |
Article in Journal/Newspaper |
author |
Emerson, L. F. Rempel, A. W. |
author_facet |
Emerson, L. F. Rempel, A. W. |
author_sort |
Emerson, L. F. |
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 |
HAL CCSD |
publishDate |
2007 |
url |
https://hal.archives-ouvertes.fr/hal-00298524 https://hal.archives-ouvertes.fr/hal-00298524/document https://hal.archives-ouvertes.fr/hal-00298524/file/tcd-1-99-2007.pdf |
genre |
The Cryosphere The Cryosphere Discussions |
genre_facet |
The Cryosphere The Cryosphere Discussions |
op_source |
ISSN: 1994-0432 EISSN: 1994-0440 The Cryosphere Discussions https://hal.archives-ouvertes.fr/hal-00298524 The Cryosphere Discussions, Copernicus, 2007, 1 (1), pp.99-122 |
op_relation |
hal-00298524 https://hal.archives-ouvertes.fr/hal-00298524 https://hal.archives-ouvertes.fr/hal-00298524/document https://hal.archives-ouvertes.fr/hal-00298524/file/tcd-1-99-2007.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1766216207929704448 |