Influence of Weak Layer Heterogeneity on Slab Avalanche Release Using a Finite Element Method

  • J. GaumeEmail author
  • G. Chambon
  • M. Naaim
  • N. Eckert
Conference paper
Part of the Springer Series in Geomechanics and Geoengineering book series (SSGG, volume 11)


Snow avalanches generally result from the collapse of a weak layer underlaying a cohesive slab. We use the finite element code Cast3m to build a complete mechanical model of the {weak layer-slab} system including inertial effects. We model the weak layer as a strain-softening interface whose properties are spatially heterogeneous. The softening accounts for the breaking of ice bridges. The overlying slab is represented by a Drucker-Prager elasto-plastic model, with post-peak softening to model the crack opening. The two key ingredients for the mechanical description of avalanches releases are the heterogeneity of the weak layer and the redistribution of stresses by elasticity of the slab. The heterogeneity is modeled through a Gaussian stochastic distribution of the friction angle with spatial correlations. We first study the effect of the weak layer’s heterogeneity and the slab depth on the release on a simple uniform slope geometry. We observe two releases types, full slope releases corresponding to a crown rupture and partial slope releases for which the traction rupture occurs inside the slope and thus only a part of the slope is released. The influence of slab depth on the relative proportion of these two rupture types, as well as on the avalanche angle distributions is also studied.


Avalanche release Shear softening Weak layer Heterogeneity Drucker-Prager 


  1. H. Conway, J. Abrahamson, Snow slope stability – a probabilistic approach. J. Glaciol. (1984)Google Scholar
  2. J. Failletaz, F. Louchet, J.-R. Grasso, Two-threshold model for scaling laws of noninteracting snow avalanches. Phys. Rev. Lett. (2004)Google Scholar
  3. B. Fyffe, M. Zaiser, The effects of snow variability on slab avalanche release. Cold Reg. Sci. Technol. (2004)Google Scholar
  4. B. Fyffe, M. Zaiser, Interplay of basal shear fracture and slab rupture in slab avalanche release. Cold Reg. Sci. Technol. (2006)Google Scholar
  5. J.B. Jamieson, C.D. Johnston, Evaluation of the shear frame test for weak snowpack layers. Ann. Glaciol. (2001)Google Scholar
  6. K. Kronholm, K. Birkeland, Integrating spatial patterns into a snow avalanche cellular automata model. Geophys. Res. Lett. (2005)Google Scholar
  7. D. McClung, Shear fracture precipitated by strain softening as a mechanism of dry slab avalanches. J. Geophys. Res. (1979)Google Scholar
  8. M. Naaim, I. Gurer, Two-phase numerical model of powder avalanche theory an application. Nat. Hazard. (2004)Google Scholar
  9. M. Naaim, T. Faug, F. Naaim-Bouvet, Dry granular flow modelling including erosion and deposition. Surv. Geophys. (2003)Google Scholar
  10. J. Schweizer, Review of dry snow slab avalanche release. Cold Reg. Sci. Technol. (1999)Google Scholar
  11. J. Schweizer, K. Kronholm, B. Jamieson, K. Birkeland, Review of spatial variability of snowpack properties and its importance for avalanche formation. Cold Reg. Sci. Technol. (2008)Google Scholar

Copyright information

© Springer Science+Business Media B.V. 2011

Authors and Affiliations

  1. 1.CemagrefSt Martin d’HeresFrance

Personalised recommendations