Role of Ice Mechanics on Snow Viscoplasticity

Abstract

AbstractThe porous structure of snow becomes denser with time under gravity, primarily due to the creep of its ice matrix with viscoplasticity. Despite investigation of this behavior at the macroscopic scale, the driving microscopic mechanisms are still not well understood. Thanks to high‐performance computing and dedicated solvers, we modeled snow elasto‐viscoplasticity with 3D images of its microstructure and different mechanical models of ice. The comparison of our numerical experiments to oedometric compression tests measured by tomography showed that ice in snow rather behaves as a heterogeneous set of ice crystals than as homogeneous polycrystalline ice. Similarly to dense ice, the basal slip system contributed at most, in the simulations, to the total snow deformation. However, in the model, the deformation accommodation between crystals was permitted by the pore space and did not require any prismatic and pyramidal slips, whereas the latter are pre‐requisite for the simulation of dense ice.