Item: Modeling the interface between two layers of snow
Title: Modeling the interface between two layers of snow
Proceedings: 2002 International Snow Science Workshop, Penticton, British Columbia
Authors: H.P. Marshall, Institute of Arctic and Alpine Research, Department of Civil, Environmental and Architectural Engineering, University of Colorado at Boulder, Boulder, CO 80309, U.S.A.
Abstract: Although dry slab avalanches in maritime climates can occur due to failure within a layer, avalanches in more continental climates are often caused by a weak bond between layers, usually as a result of the presence of surface and/or depth hoar. This can make modeling such a situation complex, as the quantitative material properties of the strength between two layers are difficult to measure and poorly understood. In addition, it is well known that the strength of snow shows a large degree of spatial variability. Measurements indicate local areas of the snowpack can have a strength which is less than the overburden stress, while the slope remains intact. The stress due the weight of snow above these areas is redistributed to areas of greater strength, a phenomenon which has been termed "bridging". Interface elements for use in finite element analysis have been developed in structural mechanics, which simulate the interface between two different materials (i.e. layers) and allow modeling of discontinuities within in a continuous system, as well as allowing the traditional elements within the model to slip relative to one another. Preliminary finite element modeling with these interface elements in the context of snow slope stability indicate that they may provide a useful tool for modeling the transfer of stress from weak to strong areas within the snowpack, as well as fracture propagation of dry slab avalanches.
Keywords: snow slope stability, finite element modeling, weak layers, interfaces
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