DOI: 10.1002/2016GL071579
论文题名: Ice flow dynamics forced by water pressure variations in subglacial granular beds
作者: Damsgaard A. ; Egholm D.L. ; Beem L.H. ; Tulaczyk S. ; Larsen N.K. ; Piotrowski J.A. ; Siegfried M.R.
刊名: Geophysical Research Letters
ISSN: 0094-8358
EISSN: 1944-8089
出版年: 2016
卷: 43, 期: 23 起始页码: 12165
结束页码: 12173
语种: 英语
英文关键词: creep
; glaciology
; granular materials
; sediments
; stick-slip
; subglacial mechanics
Scopus关键词: Bearings (machine parts)
; Chains
; Creep
; Granular materials
; Ice
; Mechanics
; Slip forming
; Stick-slip
; Computational approach
; Computational experiment
; Force chain networks
; Glaciology
; Nonlinear mechanics
; Pore-water pressures
; Saturated sediments
; Unconditional stability
; Sediments
英文摘要: Glaciers and ice streams can move by deforming underlying water-saturated sediments, and the nonlinear mechanics of these materials are often invoked as the main reason for initiation, persistence, and shutdown of fast-flowing ice streams. Existing models have failed to fully explain the internal mechanical processes driving transitions from stability to slip. We performed computational experiments that show how rearrangements of load-bearing force chains within the granular sediments drive the mechanical transitions. Cyclic variations in pore water pressure give rise to rate-dependent creeping motion at stress levels below the point of failure, while disruption of the force chain network induces fast rate-independent flow above it. This finding contrasts previous descriptions of subglacial sediment mechanics, which either assume rate dependence regardless of mechanical state or unconditional stability before the sediment yield point. Our new micromechanical computational approach is capable of reproducing important transitions between these two end-member models and can explain multimodal velocity patterns observed in glaciers, landslides, and slow-moving tremor zones. ©2016. American Geophysical Union. All Rights Reserved. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85006883477&doi=10.1002%2f2016GL071579&partnerID=40&md5=97189732aed8e546bc4a35ff1c698c17
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/9321
Appears in Collections: 科学计划与规划 气候变化与战略
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作者单位: Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California, San Diego, CA, United States
Recommended Citation:
Damsgaard A.,Egholm D.L.,Beem L.H.,et al. Ice flow dynamics forced by water pressure variations in subglacial granular beds[J]. Geophysical Research Letters,2016-01-01,43(23).