The effects of snow variability on slab avalanche release
The effects of snow variability on slab avalanche release
复制标题
积雪变化对板状雪崩释放的影响
DOI：
10.1016/j.coldregions.2004.08.004
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发表时间：
2004
影响因子：
4.1
通讯作者：
M. Zaiser
中科院分区：
文献类型：
--
作者：
B. Fyffe;M. Zaiser
干燥的雪板雪崩是由于厚厚粘性冰板下面的软弱层破裂而释放出来的。推导出了一个模型，该模型考虑了这一弱层的空间变异性以及弱区和强区之间的应力重分布。将该模型应用于软弱夹层抗剪强度随机变化的情况。结果表明，强度变化对边坡稳定性具有显著的击倒效应。推导了软弱夹层所承受的临界荷载与其平均抗剪强度和抗剪强度方差之间的关系式，并利用该方程建立了考虑波动修正的边坡稳定指标。研究了临界缺陷的性质，并对失效的前兆进行了研究。模型中引入了快速变质损伤区域的时间愈合效应，结果表明这对边坡的破坏强度影响很小。对积雪体内的应力进行了评估和讨论，并提出了考虑积雪非均质性、应变软化和内应力相互作用的破坏情形。
Dry snow slab avalanches are released by the failure of a weak layer underlying a thick cohesive slab. A model is derived which accounts for spatial variability of this weak layer and for stress redistribution between weak and strong regions. The model is applied to the case of randomly varying shear strength of the weak layer. It is demonstrated that strength variations have a dramatic knockdown effect on slope stability. An equation is derived, which relates the critical load supported by the weak layer to its mean shear strength and shear strength variance, and this equation is used to formulate a slope stability index with fluctuation corrections. The nature of the critical flaw is studied, and precursors to failure are investigated. The effect of time healing of damaged regions due to fast metamorphism is introduced into the model, and it is demonstrated that this has a minimal effect on slope failure strength. The internal stresses in the snowpack are evaluated and discussed, and a failure scenario is developed which accounts for the interplay of snowpack heterogeneity, strain softening and internal stresses.