3D simulation of Vajont disaster. Part 1: Numerical formulation and validation
3D simulation of Vajont disaster. Part 1: Numerical formulation and validation
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DOI：
10.1016/j.enggeo.2020.105854
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发表时间：
2020-12-20
影响因子：
7.4
通讯作者：
Onate, Eugenio
中科院分区：
文献类型：
--
作者：
Franci, Alessandro;Cremonesi, Massimiliano;Onate, Eugenio
本文提出了一种数值方法模拟滑坡产生的脉冲波及其应用的历史瓦洪案例研究。计算工具是基于粒子有限元法（PFEM），拉格朗日策略，结合有限元解的控制方程与一个有效的重新网格化策略，以处理大变形问题。提出的数值公式后，不同的滑坡脉冲波问题的弗劳德数范围从0.5到2.8，进行了分析，以验证所提出的方法。计算方法被证明是能够准确地再现滑坡跑出来，滑动材料和蓄水之间的动量转移，以及随之而来的波传播实验物理模型中观察到的。然后，将PFEM模型应用于瓦戎灾害的数值模拟，并采用全分辨率三维模型进行分析。数值结果进行了讨论，并与事后观测和其他计算方法的数值结果进行了比较。滑坡的速度和跳动，几何形状的存款，最大水爬高，大坝越浪，和下游山谷的水流量的结果是在良好的协议与观测和重建。为这项研究进行的校准和验证形成了在一份配套文件中提出的PFEM分析的基础，该文件最终确定为模拟在灾难发生前一年进行的实验测试中考虑的Vajont岩滑的不同场景。
This work presents a numerical method for the simulation of landslides generated impulse waves and its application to the historical Vajont case study. The computational tool is based on the Particle Finite Element Method (PFEM), a Lagrangian strategy that combines the finite element solution of the governing equations with an efficient remeshing strategy to deal with large deformation problems. After presenting the numerical formulation, different landslide impulse wave problems with Froude number ranging from 0.5 to 2.8, are analyzed to validate the proposed methodology. The computational method is shown to be able to reproduce accurately the landslide runout, the momentum transfer between the sliding material and the impounded water, and the consequent wave propagation observed in experimental physical models. Then, the PFEM model is applied to the numerical simulation of the Vajont disaster, which is analyzed with a fully-resolved three-dimensional model. The numerical results are discussed and compared to the post-event observations and the numerical results of other computational methods. The results in terms of landslide velocity and runout, geometry of the deposit, maximum water runup, dam overtopping wave, and water discharge in the downstream valley are in good agreement with observations and reconstructions. The calibration and validation performed for this study form the basis for the PFEM analyses presented in a companion paper finalized to simulate different scenarios of the Vajont rockslide considered in the experimental tests done a year before the disaster.