SLAB3D: a practice-oriented 3D software for alpine mass movement simulations

SLAB3D is a newly developed numerical model designed to address the practical needs of engineers evaluating the risks related to alpine mass movements. Based on the Material Point Method (MPM) and finite-strain elasto(visco)plasticity, SLAB3D incorporates various material models representing snow, ice, rock, and water. This enables detailed simulations of a wide range of materials under different flow regimes. In particular, a rate-dependent cohesive Drucker-Prager model, which recovers the liquid μ(I) granular rheology under flow, has been implemented and validated. Key features of SLAB3D include: 1) physical input data that can be derived from classical geotechnical or field experiments; 2) explicit simulation of bed entrainment; 3) the ability to simulate interactions with complex mitigation structures at very high resolution, achieving scales as fine as decimeters and evaluating the resulting impacts. The model is designed with practical applications in mind, integrating seamlessly with GIS tools to automate the visualization and interpretation of results in three-dimensional terrain. Validation against well-documented cases such as the Vallée de la Sionne and Salez snow avalanches, the 2023 Brienz rock avalanche, the 2017 Piz Cengalo and Vajont landslide tsunami events demonstrates SLAB3D's potential to replicate and predict real-world phenomena with high fidelity. Additionally, its application to dam overflow analysis highlights its potential for simulation-guided recommendations for the design and optimization of mitigation measures. As a tool for hazard assessment and engineering design, SLAB3D represents a promising step forward in modeling alpine mass movements, enabling us to perform tailored simulations for engineers and provide them with practical and versatile solutions.