Expérimental et théorique
Among the different types of avalanches, the "slab avalanches", made of dense snow, initiate by a long crack perpendicular to the slope, and then quickly propagate downhill during the flow. Difficult to predict, they are therefore especially dangerous for skiers and others. Prediction of their behavior remains difficult and relies mainly on empirical observations. To improve our understanding of this phenomenon, we need to understand the physics at the grain scale, and the cohesive forces involved. The objective of this project is to study how fractures appear in a cohesive granular material, how they evolve, and how they influence the flow back. These questions surpass the particular case of slab avalanches and apply to other examples of fractured flows such as landslides of cohesive soil, or, in a more industrial context, self-leveling concrete flow. To address these questions, we will combine experiments and theory-based numerical simulations. We will build up an experiment using a cohesion-controlled granular material, which has been recently synthesized to focus on the formation of fractures in a thin layer of this material and then investigate the dynamics of such system using a rotating drum. A numerical study can be done according to your taste.