3D simulation of Vajont disaster. Part 1: Numerical formulation and validation

Franci, Alessandro; Cremonesi, Massimiliano; Perego, U.; Crosta, Giovanni B.; Oñate, Eugenio

doi:10.1016/j.enggeo.2020.105854

Cited by 26 publications

(34 citation statements)

References 78 publications

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“…In this work, landslide and water are both modeled with the Particle Finite Element Method (PFEM) (Idelsohn et al, 2004;Oñate et al, 2004). Details of the PFEM are provided in the companion paper (Franci et al, 2020) and in previous publications where the method was applied to free-surface fluid dynamics problems for Newtonian (Oñate et al, 2014) and non-Newtonian (Franci and Zhang, 2018) flows, fluid-structure interaction applications (Franci et al, 2016), and to dense granular material simulation (Franci and Cremonesi, 2019). In this work, we will only recall the main characteristics of the PFEM.…”

Section: Solution Scheme With the Pfemmentioning

confidence: 99%

“…Instead, for landslide material the apparent viscosity is computed using the following frictional viscoplastic model (Franci et al, 2020)…”

Section: Solution Scheme With the Pfemmentioning

confidence: 99%

“…At the same time, the development of experimental and numerical tools for the analysis of these scenarios and the prediction of their consequences is fundamental to support the designers, as well as all the involved stakeholders. Following a companion paper (Franci et al, 2020), the Vajont catastrophic event is here reexamined to suggest what went wrong in the experimental predictions on the possible Vajont rockslide and to show how a reliable numerical model could have supported the building of a more complete view of the possible consequences and, in turn, the stakeholders' decisions.…”

Section: Introductionmentioning

confidence: 99%

“…In a companion paper (Franci et al, 2020), a PFEM model based on the implicit formulation developed by the authors (Oñate et al, 2014;Franci and Zhang, 2018;Franci and Cremonesi, 2019), was validated for three-dimensional (3D) landslide impulse wave events and applied to the numerical simulation of the Vajont disaster with a full 3D model. We note that, despite the large number of numerical models applied to the Vajont disaster (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…Based on an adequately refined three-dimensional mesh and on the PFEM modeling of the landslide and the water, Franci et al (2020) reproduced with a certain accuracy the phenomena occurred during the Vajont disaster: the detachment, runout, and stoppage of the rockslide, the 200m water runup on the northern flank of the valley, the upstream propagation of the tsunami wave along the residual Vajont lake, and the water volume overtopping the dam. The PFEM results were in good agreement with the post-event measurements and observations.…”

Section: Introductionmentioning

confidence: 99%

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3D simulation of Vajont disaster. Part 2: Multi-failure scenarios

Franci

Cremonesi

Perego

et al. 2020

Engineering Geology

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Prediction of multi-hazard events requires an informed and judicious choice of the possible scenarios. An incorrect definition of landslide conditions in terms of expected failure volume, material behavior, or boundary conditions can lead to inaccurate predictions and, in turn, to wrong engineering and risk management decisions. Reduced-scale experiments carried out two years before the Vajont disaster were carried out with a material not representative of the actual rockslide behavior and failed in not considering the simultaneous failure of the whole landslide body. Based on these inappropriate assumptions, the physical models led to wrong estimates of the safety operational level for the Vajont reservoir. This work uses the Particle Finite Element Method (PFEM) to analyze the implications of the wrong hypotheses considered in the pre-event experiments, simulating numerically the Vajont disaster for different sliding volumes and material properties. The use of the PFEM for the accurate assessment of the consequences of landslides impinging in water reservoirs has been already validated in a companion paper. In this work, we demonstrate the capabilities of a robust and reliable numerical modeling approach for the simulation of different scenarios assessing what could have been a safe operational reservoir level in the case of a landslide generated impulse wave. The three-dimensional analyses were run with a high mesh resolution and demonstrate the suitability and robustness of the PFEM model for large-scale landslide and multi-hazard events simulation.

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Section: Solution Scheme With the Pfemmentioning

confidence: 99%

“…Instead, for landslide material the apparent viscosity is computed using the following frictional viscoplastic model (Franci et al, 2020)…”

Section: Solution Scheme With the Pfemmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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3D simulation of Vajont disaster. Part 2: Multi-failure scenarios

Franci

Cremonesi

Perego

et al. 2020

Engineering Geology

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A Delaunay refinement algorithm for the particle finite element method applied to free surface flows

Leyssens,

Henry,

Lambrechts

et al. 2024

Numerical Meth Engineering

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This article proposes two contributions to the calculation of free‐surface flows using the particle finite element method (PFEM). The PFEM is based upon a Lagrangian approach: a set of particles defines the fluid and each particle is associated with a velocity vector. Then, unlike a pure Lagrangian method, all the particles are connected by a triangular mesh. The difficulty lies in locating the free surface from this mesh. It is a matter of deciding which of the elements in the mesh are part of the fluid domain, and to define a boundary—the free surface. Then, the incompressible Navier–Stokes equations are solved on the fluid domain and the particle position is updated using the velocity vector from the finite element solver. Our first contribution is to propose an approach to adapt the mesh with theoretical guarantees of quality: the mesh generation community has acquired a lot of experience and understanding about mesh adaptation approaches with guarantees of quality on the final mesh. The approach we use here is based on a Delaunay refinement strategy, allowing to insert and remove nodes while gradually improving mesh quality. We show that what is proposed allows to create stable and smooth free surface geometries. One characteristic of the PFEM is that only one fluid domain is modeled, even if its shape and topology change. It is nevertheless necessary to apply conditions on the domain boundaries. When a boundary is a free surface, the flow on the other side is not modeled, it is represented by an external pressure. On the external free surface boundary, atmospheric pressure can be imposed. Nevertheless, there may be internal free surfaces: the fluid can fully encapsulate cavities to form bubbles. The pressure required to maintain the volume of those bubbles is a priori unknown. For example, the atmospheric pressure would not be sufficient to prevent the bubbles from deflating and eventually disappearing. Our second contribution is to propose a multi‐point constraint approach to enforce global incompressibility of those empty bubbles. We show that this approach allows to accurately model bubbly flows that involve two fluids with large density differences, for instance water and air, while only modeling the heavier fluid.

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