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Three-dimensional and real-scale modeling of flow regimes in dense snow avalanches
Landslides ( IF 6.7 ) Pub Date : 2021-07-29 , DOI: 10.1007/s10346-021-01692-8
Xingyue Li 1 , Betty Sovilla 2 , Chenfanfu Jiang 3 , Johan Gaume 1, 2
Affiliation  

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.



中文翻译:

密集雪崩中流态的三维和实尺度建模

雪崩在全球范围内造成人员伤亡和经济损失,是山区最危险的重力灾害之一。据报道,雪崩中有各种流动行为,这使得它们很难被彻底理解和缓解。用于模拟雪崩的现有流行数值方法主要采用深度平均模型,该模型计算效率高,但未能捕捉沿流深度方向的重要特征,例如致密化和颗粒化。本研究应用三维 (3D) 质点法 (MPM) 来探索复杂真实地形上不同状态下的雪崩。对雪崩从释放到沉积的流动特征进行了综合表征,以识别不同的状态。尤其,在不同的模拟雪崩释放后不久,就发现了脆性和韧性断裂。在流动过程中,对局部雪密度变化的分析表明,雪粒化需要雪破碎和压实的适当组合。相比之下,无凝聚力的颗粒流和塞流主要分别受膨胀和压实硬化控制。雪崩沉积物具有不同的纹理特征,包括光滑的表面、带有雪颗粒的粗糙表面,以及在湿雪崩沉积物中经常报道的压实剪切面的表面。最后,MPM 模型通过发生在瑞士 Vallée de la Sionne 的真实雪崩得到验证。MPM 框架已被证明是一种很有前途的数值工具,可用于探索不同状态下各种雪崩的复杂行为,以更好地了解雪崩动力学。将来,该框架可以扩展到研究其他类型的重力质量运动,例如岩石/冰川雪崩和泥石流,并实施修改后的本构定律。

更新日期:2021-07-30
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