Evaluating snow weak-layer failure parameters through inverse finite element modelling of shaking-platform experiments

Abstract

Abstract. Snowpack weak layers may fail due to excess stresses of various natures, caused by snowfall, skiers, explosions or strong ground motion due to earthquakes, and lead to snow avalanches. This research presents a numerical model describing the failure of "sandwich" snow samples subjected to shaking. The finite element model treats weak layers as interfaces with variable mechanical parameters. This approach is validated by reproducing cyclic loading snow fracture experiments. The model evaluation revealed that the Mohr-Coulomb failure criterion, governed by cohesion and friction angle, was adequate to describe the experiments. The model showed the complex, non-homogeneous stress evolution within the snow samples and especially the importance of tension on fracture initiation at the edges of the weak layer, caused by dynamic stresses due to shaking. Accordingly, a simplified analytical solution, ignoring the inhomogeneity of tangential and normal stresses along the failure plane, may incorrectly estimate the shear strength of the weak layers. The values for "best fit" cohesion and friction angle were ≈ 1.6 kPa and 22.5-60 • . These may constitute valuable first approximations in mechanical models used for avalanche forecasting.

Earthquake‐Induced Chains of Geologic Hazards: Patterns, Mechanisms, and Impacts

“…Shaking tables are experimental devices that can be used to investigate the response of model slopes, artificial structures, or building components to seismic shaking or other types of vibration (Figure ). They are particularly useful in studying the initiation mechanisms of EQTLs, for back‐analyzing the behavior of landslides that lacked adequate monitoring (R. Huang et al, ) and for measuring mechanical parameters of weak layers conducive to failure (e.g., Podolskiy et al, ). In fact, the limited information on the strength properties of soils and rocks under dynamic forcing hampers the applicability of advanced physically based numerical models that account for seismic shaking explicitly.…”

Determination of failure envelope for faceted snow through numerical simulations

“…Podolskiy et al (2015) used Mohr-Coulomb failure criteria for representing weak layers as interfaces and suggested a necessity of further testing for non-linear shapes of Mohr-Coulomb. This was confirmed by Reiweger et al (2015) who modeled the failure envelope by MCC.…”

“…Hagenmuller et al (2014a) reported that the mechanical response of snow is directly dependent on minimum cut density (MCD) and determined its tensile strength through numerical simulations. Recently failure envelopes for weak snow layers were developed using discrete and finite element modeling (DEM and FEM respectively) from idealized 2D model (Gaume et al, 2014;Podolskiy et al, 2015) under the combined effect of compressive and shear loading. Reiweger et al (2015) represented the failure criterion for weak snow layers in the normal stress-shear stress by Mohr-Coulomb with Cap (MCC) envelope.…”