Three-dimensional and real-scale modeling of flow regimes in dense snow avalanches

Abstract

Snow avalanches cause fatalities and economic loss worldwide and are one of the most dangerous gravitational hazards in mountainous regions. Various flow behaviors have been reported in snow avalanches, making them challenging to be thoroughly understood and mitigated. Existing popular numerical approaches for modeling snow avalanches predominantly adopt depth-averaged models, which are computationally efficient but fail to capture important features along the flow depth direction such as densification and granulation. This study applies a three-dimensional (3D) material point method (MPM) to explore snow avalanches in different regimes on a complex real terrain. Flow features of the snow avalanches from release to deposition are comprehensively characterized for identification of the different regimes. In particular, brittle and ductile fractures are identified in the different modeled avalanches shortly after their release. During the flow, the analysis of local snow density variation reveals that snow granulation requires an appropriate combination of snow fracture and compaction. In contrast, cohesionless granular flows and plug flows are mainly governed by expansion and compaction hardening, respectively. Distinct textures of avalanche deposits are characterized, including a smooth surface, rough surfaces with snow granules, as well as a surface showing compacting shear planes often reported in wet snow avalanche deposits. Finally, the MPM modeling is verified with a real snow avalanche that occurred at Vallée de la Sionne, Switzerland. The MPM framework has been proven as a promising numerical tool for exploring complex behavior of a wide range of snow avalanches in different regimes to better understand avalanche dynamics. In the future, this framework can be extended to study other types of gravitational mass movements such as rock/glacier avalanches and debris flows with implementation of modified constitutive laws.

Numerical investigation of the effect of cohesion and ground friction on snow avalanches flow regimes

“…[ 14 ] and simulated by Li et al . [ 66 ] was not modeled here. Fig 6i shows aggregates due to breakage only.…”

Detrainment and braking of snow avalanches interacting with forests

“…This study aims to quantify the amount of snow caught in forests and explore the mechanism of the detrainment, with comprehensive consideration of different avalanche features and forest configurations. We use a three-dimensional material point method (3D MPM), by which the fractures, collisions, and large deformations involved in snow avalanches can be well captured (Gaume et al, 2018(Gaume et al, , 2019Li et al, 2020Li et al, , 2021. More importantly, individual trees and their interactions with snow avalanches can be explicitly modelled without relying on empirical laws.…”

Scalable three‐dimensional hybrid continuum‐discrete multiscale modeling of granular media

“…Moreover, the 2D setting may also prevent modeling of some practical problems with realistic topography. 30,31 Therefore, a true 3D multiscale modeling framework is highly desirable. Second, though the extension from 2D to 3D is conceptually straightforward, it remains challenging from an implementation perspective.…”

“…To capture the influence of loading conditions on the failure behavior, 3D modeling is required. Moreover, the 2D setting may also prevent modeling of some practical problems with realistic topography 30,31 . Therefore, a true 3D multiscale modeling framework is highly desirable.…”