In-situ measurement of the strength of deforming subglacial till
Abstract The shear strength of deforming till beneath Storglaciären, Sweden, was continuously measured with a new instrument, a “dragometer”. A cylinder with conical ends, roughened with till from the glacier bed, was dragged through the till, and the force on the cylinder was recorded. Consistent w...
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Language: | English |
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Cambridge University Press (CUP)
1994
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Online Access: | http://dx.doi.org/10.1017/s0022143000012375 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000012375 |
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crcambridgeupr:10.1017/s0022143000012375 2024-09-15T18:15:38+00:00 In-situ measurement of the strength of deforming subglacial till Iverson, Neal R. Jansson, Peter Hooke, Roger Leb. 1994 http://dx.doi.org/10.1017/s0022143000012375 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000012375 en eng Cambridge University Press (CUP) Journal of Glaciology volume 40, issue 136, page 497-503 ISSN 0022-1430 1727-5652 journal-article 1994 crcambridgeupr https://doi.org/10.1017/s0022143000012375 2024-08-28T04:03:10Z Abstract The shear strength of deforming till beneath Storglaciären, Sweden, was continuously measured with a new instrument, a “dragometer”. A cylinder with conical ends, roughened with till from the glacier bed, was dragged through the till, and the force on the cylinder was recorded. Consistent with studies of cone penetration in soils, it was assumed that the till behaves as a Coulomb plastic material. This allows the residual strength of the till to be calculated from the measured force. Results from laboratory experiments confirm the validity of the analytical procedure. The average residual strength of the till was ∼55 kPa. A source of error is the potential generation of pore pressure in excess of hydrostatic ahead of the cylinder, which could significantly weaken the till. Calculations indicate that excess pore pressure did not develop during the experiment, but could develop during similar experiments beneath rapidly sliding glaciers with less permeable basal till layers. Article in Journal/Newspaper Journal of Glaciology Cambridge University Press Journal of Glaciology 40 136 497 503 |
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Open Polar |
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Cambridge University Press |
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English |
description |
Abstract The shear strength of deforming till beneath Storglaciären, Sweden, was continuously measured with a new instrument, a “dragometer”. A cylinder with conical ends, roughened with till from the glacier bed, was dragged through the till, and the force on the cylinder was recorded. Consistent with studies of cone penetration in soils, it was assumed that the till behaves as a Coulomb plastic material. This allows the residual strength of the till to be calculated from the measured force. Results from laboratory experiments confirm the validity of the analytical procedure. The average residual strength of the till was ∼55 kPa. A source of error is the potential generation of pore pressure in excess of hydrostatic ahead of the cylinder, which could significantly weaken the till. Calculations indicate that excess pore pressure did not develop during the experiment, but could develop during similar experiments beneath rapidly sliding glaciers with less permeable basal till layers. |
format |
Article in Journal/Newspaper |
author |
Iverson, Neal R. Jansson, Peter Hooke, Roger Leb. |
spellingShingle |
Iverson, Neal R. Jansson, Peter Hooke, Roger Leb. In-situ measurement of the strength of deforming subglacial till |
author_facet |
Iverson, Neal R. Jansson, Peter Hooke, Roger Leb. |
author_sort |
Iverson, Neal R. |
title |
In-situ measurement of the strength of deforming subglacial till |
title_short |
In-situ measurement of the strength of deforming subglacial till |
title_full |
In-situ measurement of the strength of deforming subglacial till |
title_fullStr |
In-situ measurement of the strength of deforming subglacial till |
title_full_unstemmed |
In-situ measurement of the strength of deforming subglacial till |
title_sort |
in-situ measurement of the strength of deforming subglacial till |
publisher |
Cambridge University Press (CUP) |
publishDate |
1994 |
url |
http://dx.doi.org/10.1017/s0022143000012375 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000012375 |
genre |
Journal of Glaciology |
genre_facet |
Journal of Glaciology |
op_source |
Journal of Glaciology volume 40, issue 136, page 497-503 ISSN 0022-1430 1727-5652 |
op_doi |
https://doi.org/10.1017/s0022143000012375 |
container_title |
Journal of Glaciology |
container_volume |
40 |
container_issue |
136 |
container_start_page |
497 |
op_container_end_page |
503 |
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1810453509331484672 |