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The tertiary creep of polycrystalline ice: experimental evidence for stress-dependent levels of strain-rate enhancement

Citation

Treverrow, A and Budd, WF and Jacka, TH and Warner, RC, The tertiary creep of polycrystalline ice: experimental evidence for stress-dependent levels of strain-rate enhancement, Journal of Glaciology, 58, (208) pp. 301-314. ISSN 0022-1430 (2012) [Refereed Article]


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Copyright Statement

Copyright 2012 International Glaciological Society

Official URL: http://www.igsoc.org/journal/

DOI: doi:10.3189/2012JoG11J149

Abstract

Laboratory creep deformation experiments have been conducted on initially isotropic laboratory-made samples of polycrystalline ice. Steady-state tertiary creep rates, ter, were determined at strains exceeding 10% in either uniaxial-compression or simple-shear experiments. Isotropic minimum strain rates, min, determined at ∼1% strain, provide a reference for comparing the relative magnitude of tertiary creep rates in shear and compression through the use of strain-rate enhancement factors, E, defined as the ratio of corresponding tertiary and isotropic minimum creep rates, i.e. E = ter/min. The magnitude of strain-rate enhancement in simple shear was found to exceed that in uniaxial compression by a constant factor of 2.3. Results of experiments conducted at octahedral shear stresses of τo = 0.040.80 MPa indicate a creep power-law stress exponent of n = 3 for isotropic minimum creep rates and n = 3.5 for tertiary creep rates. The difference in stress exponents for minimum and tertiary creep regimes can be interpreted as a τo stress-dependent level of strain-rate enhancement, i.e. E α τ1/2o. The implications of these results for deformation in complex multicomponent stress configurations and at stresses below those used in the current experiments are discussed.

Item Details

Item Type:Refereed Article
Keywords:ice dynamics, ice rheology
Research Division:Earth Sciences
Research Group:Physical Geography and Environmental Geoscience
Research Field:Glaciology
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Earth Sciences
Author:Treverrow, A (Dr Adam Treverrow)
Author:Budd, WF (Professor William Budd)
Author:Jacka, TH (Dr Jo Jacka)
Author:Warner, RC (Dr Roland Warner)
ID Code:78600
Year Published:2012
Web of Science® Times Cited:14
Deposited By:CRC-Antarctic Climate & Ecosystems
Deposited On:2012-07-09
Last Modified:2015-07-13
Downloads:0

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