Multiscale characterisation of weak snow layer mechanical behaviour

The destabilisation and failure of weak snow layers play a major role in the release of snow avalanches, in particular slab avalanches. These weak layers are generally thin – only a few snow grains thick – and characterised by loose, unstable, and collapsible microstructures. In order to develop realistic slope-scale avalanche release models and progress in the prediction of natural hazards in mountainous environments, a better description of the mechanical behaviour of these weak snow layers, accounting for their complex microstructure, is required.

In this project, images of the microstructure of snow samples obtained by X-ray microtomography will be implemented in a 3D discrete element model (DEM) to carry out numerical experimentations and explore, the mechanical response of weak snow layers submitted to shear and compression loading.

Through numerical homogenization approaches, the results of these simulations will then be used to infer effective constitutive laws representative of the mechanical behaviour of weak snow layers. The final goal is to implement this micromechanical model of snow in a continuous model at the slope scale in order to investigate the influence of weak snow layers on avalanche release mechanisms.

This project is expected to give a unique multiscale framework to investigate avalanche release mechanisms. Such microstructure-based tool for the assessment of avalanche release conditions would be the first of its kind.