Granular Avalanche Impact on a Structure using DEM and FEM

Mountain regions face a variety of natural hazards that menace infrastructure and the people living in these areas. Human activity in these areas is intensifying, making hazard analysis and risk mitigation critical. Switzerland, with its densely populated alpine landscape, is a good example of these challenges to involve. The country is regularly exposed to natural hazards such as avalanches, rockfalls, floods and landslides. Recent events have highlighted the need to design for preventive measures and protective structures. In Easter 2025, a major avalanche hit the "Galerie des Toules". This protection tunnel, located on the Great St. Bernard Pass, was severely damaged. The incident disrupted a key transit route between Switzerland and Italy. It showed that even engineered structures can fail. The avalanche followed important snowfall and rapid warming, conditions that are becoming more frequent with climate change [2]. Even more alarming, in May 2025, a major collapse occurred above the village of Blatten, in the Lötschental valley. A section of the mountain has shown signs of destabilization, culminating in a collapse hitting the "glacier du Birch" below. According to experts, climate change likely played a key role. Over the last 10–15 years, warming has reduced the permafrost’s stability. As a result, the area saw a sharp rise in rockfall events. These rockfalls added important loads to the glacier, increasing its speed and instability. The glacier was already in a fragile state and recent collapses made the situation even worse [3]. These cases highlight the dynamic nature of mountain hazards and focus on the importance of studying protective measures. They also expose the need for collaboration between monitoring, modeling and risk management tools. This project investigates how structures respond to flow and rockfall hazards in alpine environments. By examining how protective structures interact with granular flows, such as avalanches, the project aims to improve our understanding of impact mechanisms. Through simulations and a simplified case study, this work contributes also to a more general interest in protecting mountain regions from natural hazards and risks.