3D elastoplastic simulation of ski-triggered snow slab avalanches

TL;DR

This study uses 3D elastoplastic finite element simulations to analyze how skier-induced loads affect snow slab stability, considering layered structures and plastic deformation to better predict avalanche triggers.

Contribution

It introduces a 3D elastoplastic simulation approach with Mohr-Coulomb-Cap modeling to realistically analyze stress and deformation in layered snow slabs under skier loads.

Findings

Hard layers create bridging effects that distribute stress.

Layered snow alters stress distribution on the weak layer.

Plastic deformation relates to critical crack length in snow slabs.

Abstract

The stability of dry-snow avalanches is strongly dependent on the interaction between the snow slab above a weak-layer and, as presented in this work, the skier induced load. This induced load causes an additional stress field on the slab which eventually triggers an avalanche. I present the results of 3D finite element simulations in an elastoplastic domain. The plastic deformation of the weak-layer follows the Mohr-Coulomb-Cap model which provides a more realistic model as a pure elastic approach. I investigate how the stress field on top of the weak-layer changes if one is skiing down-slope or parallel to the slope. A layered snow slab changes the stress on top of the weak-layer and to investigate these changes I simulated two different representative layered slabs. One containing only soft layers to investigate how the weak layer is affected by the ski induced stress and the other hard-soft-hard layer to examine bridge effects caused by the hard layers. A hard layer in the snow slab forms a sort of bridge which spreads the induced stress over a larger lateral distance, at the same time decreasing the stress to the layers below the bridge. Furthermore, I show a possible connection between the plastic deformation and the critical crack length.