Micro-mechanical insights into the dynamics of crack propagation in snow fracture experiments
Abstract Dry-snow slab avalanches result from crack propagation in a highly porous weak layer buried within a stratified and metastable snowpack. While our understanding of slab avalanche mechanisms improved with recent experimental and numerical advances, fundamental micro-mechanical processes rema...
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Nature Portfolio
2021
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oai:doaj.org-article:bb057f31a0094da484be0eace389574f2021-12-02T18:24:55ZMicro-mechanical insights into the dynamics of crack propagation in snow fracture experiments10.1038/s41598-021-90910-32045-2322https://doaj.org/article/bb057f31a0094da484be0eace389574f2021-06-01T00:00:00Zhttps://doi.org/10.1038/s41598-021-90910-3https://doaj.org/toc/2045-2322Abstract Dry-snow slab avalanches result from crack propagation in a highly porous weak layer buried within a stratified and metastable snowpack. While our understanding of slab avalanche mechanisms improved with recent experimental and numerical advances, fundamental micro-mechanical processes remain poorly understood due to a lack of non-invasive monitoring techniques. Using a novel discrete micro-mechanical model, we reproduced crack propagation dynamics observed in field experiments, which employ the propagation saw test. The detailed microscopic analysis of weak layer stresses and bond breaking allowed us to define the crack tip location of closing crack faces, analyze its spatio-temporal characteristics and monitor the evolution of stress concentrations and the fracture process zone both in transient and steady-state regimes. Results highlight the occurrence of a steady state in crack speed and stress conditions for sufficiently long crack propagation distances (> 4 m). Crack propagation without external driving force except gravity is possible due to the local mixed-mode shear-compression stress nature at the crack tip induced by slab bending and weak layer volumetric collapse. Our result shed light into the microscopic origin of dynamic crack propagation in snow slab avalanche release that eventually will improve the evaluation of avalanche release sizes and thus hazard management and forecasting in mountainous regions.Grégoire BobillierBastian BergfeldJürg DualJohan GaumeAlec van HerwijnenJürg SchweizerNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 11, Iss 1, Pp 1-15 (2021) |
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DOAJ |
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Medicine R Science Q |
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Medicine R Science Q Grégoire Bobillier Bastian Bergfeld Jürg Dual Johan Gaume Alec van Herwijnen Jürg Schweizer Micro-mechanical insights into the dynamics of crack propagation in snow fracture experiments |
| description |
Abstract Dry-snow slab avalanches result from crack propagation in a highly porous weak layer buried within a stratified and metastable snowpack. While our understanding of slab avalanche mechanisms improved with recent experimental and numerical advances, fundamental micro-mechanical processes remain poorly understood due to a lack of non-invasive monitoring techniques. Using a novel discrete micro-mechanical model, we reproduced crack propagation dynamics observed in field experiments, which employ the propagation saw test. The detailed microscopic analysis of weak layer stresses and bond breaking allowed us to define the crack tip location of closing crack faces, analyze its spatio-temporal characteristics and monitor the evolution of stress concentrations and the fracture process zone both in transient and steady-state regimes. Results highlight the occurrence of a steady state in crack speed and stress conditions for sufficiently long crack propagation distances (> 4 m). Crack propagation without external driving force except gravity is possible due to the local mixed-mode shear-compression stress nature at the crack tip induced by slab bending and weak layer volumetric collapse. Our result shed light into the microscopic origin of dynamic crack propagation in snow slab avalanche release that eventually will improve the evaluation of avalanche release sizes and thus hazard management and forecasting in mountainous regions. |
| format |
article |
| author |
Grégoire Bobillier Bastian Bergfeld Jürg Dual Johan Gaume Alec van Herwijnen Jürg Schweizer |
| author_facet |
Grégoire Bobillier Bastian Bergfeld Jürg Dual Johan Gaume Alec van Herwijnen Jürg Schweizer |
| author_sort |
Grégoire Bobillier |
| title |
Micro-mechanical insights into the dynamics of crack propagation in snow fracture experiments |
| title_short |
Micro-mechanical insights into the dynamics of crack propagation in snow fracture experiments |
| title_full |
Micro-mechanical insights into the dynamics of crack propagation in snow fracture experiments |
| title_fullStr |
Micro-mechanical insights into the dynamics of crack propagation in snow fracture experiments |
| title_full_unstemmed |
Micro-mechanical insights into the dynamics of crack propagation in snow fracture experiments |
| title_sort |
micro-mechanical insights into the dynamics of crack propagation in snow fracture experiments |
| publisher |
Nature Portfolio |
| publishDate |
2021 |
| url |
https://doaj.org/article/bb057f31a0094da484be0eace389574f |
| work_keys_str_mv |
AT gregoirebobillier micromechanicalinsightsintothedynamicsofcrackpropagationinsnowfractureexperiments AT bastianbergfeld micromechanicalinsightsintothedynamicsofcrackpropagationinsnowfractureexperiments AT jurgdual micromechanicalinsightsintothedynamicsofcrackpropagationinsnowfractureexperiments AT johangaume micromechanicalinsightsintothedynamicsofcrackpropagationinsnowfractureexperiments AT alecvanherwijnen micromechanicalinsightsintothedynamicsofcrackpropagationinsnowfractureexperiments AT jurgschweizer micromechanicalinsightsintothedynamicsofcrackpropagationinsnowfractureexperiments |
| _version_ |
1718378119889420288 |