Modelling compaction band formation in snow: a FEM application of an elasto-visco-plastic model

The mechanics of snow plays a critical role in assessing and mitigating hazards associated with snow and avalanches in mountain and cold environments. Accurately modelling the mechanical behaviour of snow remains a significant challenge, requiring the development of reliable constitutive models and advanced numerical methods. These efforts are particularly important because of the unique characteristics of snow, such as strain-rate sensitivity, sintering and degradation phenomena, localisation of the deformation, etc.

This study employs the elasto-visco-plastic constitutive model recently proposed by the authors [1, 2] to simulate compaction band formation in snow samples subjected to confined compression conditions. We refer to the experimental findings described by Barraclough et al. (2017) [3], which demonstrated the onset of compaction bands in snow specimens subjected to compression in plane strain conditions. The results revealed a clear dependency of the response on the applied strain rate: at low strain rates (typically below the threshold of 10^-4 s^-1) the samples exhibited homogeneous deformation. Conversely, when the strain rate exceeded this threshold, deformation localised, forming distinct compaction bands. The new constitutive model, implemented within the finite element software Abaqus/Standard through a custom User MATerial (UMAT) subroutine, has been used to simulate the behaviour observed in the tests.

The application of the proposed constitutive model to this problem demonstrates its ability to accurately replicate the specific phenomenon observed in laboratory experiments. This study underscores the potential of numerical simulations to enhance the understanding of snow deformation mechanisms, with promising implications for simulating the behaviour of snow at both in-situ and laboratory scales, as well as for improving avalanche hazard and risk assessment.

[1] Vallero, G., Barbero, M., Barpi, F., Borri-Brunetto, M., De Biagi, V. (2025). An elasto-visco-plastic constitutive model for snow: Theory and finite element implementation. Computer Methods in Applied Mechanics and Engineering, 433, 117465.

[2] Vallero, G. (2024). A visco-plastic constitutive model for snow. Theoretical basis and numerical implementation. PhD thesis. Politecnico di Torino.

[3] Barraclough, T. W., Blackford, J. R., Liebenstein, S., Sandfeld, S., Stratford, T. J., Weinländer, G., Zaiser, M. (2017). Propagating compaction bands in confined compression of snow. Nature Physics, 13(3), 272-275.