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Résumé de la présentation :
We present a newly developed numerical model aimed at supporting engineers in the assessment of alpine mass-movement hazards. Based on the Material Point Method (MPM) and finite-strain elasto(visco)plasticity, the model can represent snow, ice, rock, and water, enabling detailed simulations across a wide range of materials and flow regimes. Rate-dependent cohesive Drucker–Prager and Modified Cam Clay formulations, both recovering the liquid μ(I) granular rheology under flow conditions, have been implemented and validated. The model offers several key advantages: 1) physically based input parameters that can be constrained from standard geotechnical or field experiments; 2) explicit simulation of bed entrainment; and 3) high-resolution simulations of interactions with complex terrain and mitigation structures, down to decimeter scales, allowing impact assessment. It is also designed for practical applications, with seamless GIS integration for automated visualization and interpretation of results in three-dimensional terrain. Validation against well-documented case studies demonstrates the model’s ability to reproduce and predict real events with high fidelity. In particular, applications to the 2023 Brienz rock avalanche and the 2025 Blatten rock–ice avalanche showed good runout predictions. For the Blatten event, discrepancies in deposit distribution and seismic signals revealed limitations of a single-phase frictional description and pointed to possible liquefaction processes. These effects were captured phenomenologically using a μ(I)-type rheology, although future two-phase formulations are expected to improve the description further. The model has also been applied to scenarios involving potential catastrophic rock avalanches and dam overflow, illustrating its value for prediction as well as for the design and optimization of mitigation measures. As a tool for hazard assessment and engineering design, it provides a versatile and promising framework for tailored simulations of alpine mass movements.
Le chercheur invité :
Johan Gaume is Associate Professor of Alpine Mass Movements at ETH Zürich, a position which is jointly affiliated with the WSL Institute for Snow and Avalanche Research SLF in Davos, Switzerland. He is a member of the Science Alliance of POW – Protect our Winter and member of the Editorial Board of Computational Particle Mechanics. His research interest is in the initiation and propagation of gravitational mass movements, including the development of multiscale methods based on computational geomechanics validated using laboratory and field experiments. His work on snow avalanches was extended to model glacier calving and tsunamis as well as multiphase alpine mass movements. He is also known for proposing, a plausible explanation to the Dyatlov Pass Incident, a famous Russian Cold case. His work improves the physical understanding of slope instability and mass flow prediction with impacts on applied research related to risk assessment and management in mountainous regions.