Item: Unified modeling of the release and flow of snow avalanches using the Material Point Method
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Title: Unified modeling of the release and flow of snow avalanches using the Material Point Method
Proceedings: International Snow Science Workshop Proceedings 2018, Innsbruck, Austria
Authors:
- Johan Gaume [ EPFL - Swiss Federal Institute of Technology, Lausanne, Switzerland ] [ WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland ]
- Theodore F. Gast [ University of California Los Angeles, USA ] [ Jixie Effects, Los Angeles, USA ]
- Joseph Teran [ University of California Los Angeles, USA ] [ Jixie Effects, Los Angeles, USA ]
- Alec van Herwijnen [ WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland ]
- Chenfanfu Jiang [ Jixie Effects, Los Angeles, USA ] [ University of Pennsylvania, Philadelphia, USA ]
Date: 2018-10-07
Abstract: Snow slab avalanches start with the failure of a weak snow layer buried below a cohesive snow slab. After failure, the very porous character of the weak layer leads to its volumetric collapse and thus closing of crack faces due to the weight of the overlaying slab. This complex process, generally referred to as anticrack, explains why avalanches can be remotely triggered from flat terrain. On the basis of a new elastoplastic model for porous cohesive materials and the Material Point Method, we accurately reproduce the dynamics of anticracks observed in propagation saw tests as well as the subsequent detachment of the slab and the flow of the avalanche. In particular, we performed two and three dimensional slope scale simulations of both the release and flow of slab avalanches triggered either directly or remotely. We describe in details the fracture and flow dynamics on a realistic topography and focus on the plastic strain, stress invariants, propagation speed and flow velocity. Furthermore, we show that slab fracture always starts from the top in the Propagation Saw Test while it systematically initiates at the interface with the weak layer at the crown of slope-scale simulations in agreement with field observations. Our unified model represents a significant step forward as it allows simulating the entire avalanche process, from failure initiation to crack propagation and to solid-fluid phase transitions, which is of paramount importance to mitigate and forecast snow avalanches as well as gravitational hazards in general.
Language of Article: English
Presenters:
Keywords: Snow avalanche, crack propagation, slab, weak layer, elastoplasticity, MPM
Page Number(s): 1-5
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Digital Abstract Not Available
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