On the Stability of Deep‐Seated Landslides. The Cases of Vaiont (Italy) and Shuping (Three Gorges Dam, China)
On the Stability of Deep‐Seated Landslides. The Cases of Vaiont (Italy) and Shuping (Three Gorges Dam, China)
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DOI：
10.1029/2019jf005203
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发表时间：
2020-07
期刊：
影响因子：
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通讯作者：
C. Seguí;H. Rattez;M. Veveakis
中科院分区：
文献类型：
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作者：
C. Seguí;H. Rattez;M. Veveakis
当深层滑坡突然发生故障时，可能会对人类生活和基础设施造成灾难性影响。这些事件是毁灭性的，因为涉及大量的土壤和岩体，而且往往是长期运行。本研究提出了一种基于能量的方法来确定滑坡何时变得不稳定，给出了可测量变量（速度和基底温度）的临界值，可以部署修复行动。这项工作的重点是大型古代滑坡重新激活大坝相关的地下水位变化，修改滑坡的稳定性。这项工作的主要假设是，大部分深层滑坡的变形集中在形成滑动面的薄基底剪切带上。特别是，这一假设允许将深部滑坡近似为在粘塑性剪切带上滑动的弹性/刚性块体，其特征是弱相，如膨胀粘土。当滑坡移动时，它会在剪切带中引起摩擦，从而提高粘土的温度，直到它们变得不稳定并通过热失控不稳定而灾难性地坍塌。将该模型应用于北方意大利的Vaiont滑坡和中国三峡大坝旁的树坪滑坡。该模型的结果再现了两个滑坡的滑动行为，并提供了稳定性的临界点的约束。
Deep‐seated landslides can have catastrophic impacts on human life and infrastructure when they suddenly fail. These events are devastating because of the large volumes of soil and rock masses involved and their often long runout. The present study suggests an energy‐based method to determine when a landslide becomes unstable, giving critical values for measurable variables (velocity and basal temperature) up to which remediation actions can be deployed. This work focuses on large ancient landslides reactivated by dam‐related water table variations that modify landslide stability. The main hypothesis of this work is that most of the deformation of deep‐seated landslides is concentrated on a thin, basal shear band forming the sliding surface. In particular, this assumption allows an approximation of deep‐seated landslides as elastic/rigid blocks sliding over a viscoplastic shear band, featuring weak phases like expansive clays. When the landslide moves, it causes friction in the shear band that raises the temperature of the clays until they become unstable and collapse catastrophically through a thermal runaway instability. The model is applied to the Vaiont landslide in Northern Italy and the Shuping landslide next to the Three Gorges Dam in China. The results of the model reproduce the sliding behavior of both landslides and provide constraints on the critical points of stability.