Numerical modeling of 2‐D granular step collapse on erodible and nonerodible surface

Crosta, Giovanni B.; Imposimato, S.; Roddeman, D.

doi:10.1029/2008jf001186

Cited by 123 publications

(106 citation statements)

References 50 publications

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“…Note that small-scale laboratory experiments of granular collapse are well reproduced by finite-element numerical models using a Coulomb friction law with a constant friction coefficient 49 . Experimental studies 4 show that granular collapse over beds with slope angles up to 22°have a maximum velocity of about 2 m s À 1 , that is, o4 m s À 1 , so that equation (3) 4,51 show that the maximum velocity is a function of ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi ffi gH 0 cos y p .…”

Section: Resultsmentioning

confidence: 94%

Frictional velocity-weakening in landslides on Earth and on other planetary bodies

2014

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One of the ultimate goals in landslide hazard assessment is to predict maximum landslide extension and velocity. Despite much work, the physical processes governing energy dissipation during these natural granular flows remain uncertain. Field observations show that large landslides travel over unexpectedly long distances, suggesting low dissipation. Numerical simulations of landslides require a small friction coefficient to reproduce the extension of their deposits. Here, based on analytical and numerical solutions for granular flows constrained by remote-sensing observations, we develop a consistent method to estimate the effective friction coefficient of landslides. This method uses a constant basal friction coefficient that reproduces the first-order landslide properties. We show that friction decreases with increasing volume or, more fundamentally, with increasing sliding velocity. Inspired by frictional weakening mechanisms thought to operate during earthquakes, we propose an empirical velocity-weakening friction law under a unifying phenomenological framework applicable to small and large landslides observed on Earth and beyond.

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Section: Resultsmentioning

confidence: 94%

Frictional velocity-weakening in landslides on Earth and on other planetary bodies

2014

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“…For this reason, many researchers have favoured continuum methods such as the adaptive Lagrangian-Eulerian finite element method (ALE FEM). Crosta et al [9] presented a series of simulation using ALE FEM with a Mohr-Coulomb model. The results were in line with the experimental results.…”

Section: Simulating the Column Collapsementioning

confidence: 99%

The role of constitutive models in MPM simulations of granular column collapses

Fern

Soga

2016

Acta Geotech.

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The granular column collapse is a well-established experiment which consists of having a vertical column of granular material on a flat surface and letting it collapse by gravity. Despite its simplicity in execution, the numerical modelling of a column collapse remains challenging. So far, much attention has been dedicated in assessing the ability of various numerical methods in modelling the large deformation and little to the role of the constitutive model on both the triggering mechanism and the flow behaviour. Furthermore, the influence of the initial density, and its associated dilatancy and strength characteristics, have never been included in the analyses. Most past numerical investigations had relied on simple constitutive relations which do not consider the softening behaviours. The aim of this study is to illustrate the influence of the constitutive model on the on-set of failure, the flow behaviour and the deposition profile using the material point method. Three constitutive models were used to simulate the collapse of two granular columns with different geometries and for two densities. The results of the simulations showed that the constitutive model had a twofold influence on the collapse behaviour. It defined the volume of the mobilised mass which spread along the flat surface and controlled the dissipation of its energy. The initial density was found to enhance the failure angle and flow behaviours and was more significant for small columns than for larger ones. The analysis of the potential energy of the mobilised mass explained the existence of two collapse regimes.

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“…Currently, there is a lot of interests in exploring the failure mechanism and characteristics of fast and long runout rockslides via numerical modelling (Utili et al 2014;Crosta et al 2013;Sitar et al 2005;Zhao et al 2012;Boon 2013;Quecedo et al 2004;Crosta et al 2006Crosta et al , 2009Crosta and Frattini 2008). In this paper, a quasi-3D DEM-CFD model is used to investigate the mechanical and hydraulic behaviour of the Vajont rockslide.…”

Section: Introductionmentioning

confidence: 99%

Rockslide and Impulse Wave Modelling in the Vajont Reservoir by DEM-CFD Analyses

2015

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This paper investigates the generation of hydrodynamic water waves due to rockslides plunging into a water reservoir. Quasi-3D DEM analyses in plane strain by a coupled DEM-CFD code are adopted to simulate the rockslide from its onset to the impact with the still water and the subsequent generation of the wave. The employed numerical tools and upscaling of hydraulic properties allow predicting a physical response in broad agreement with the observations notwithstanding the assumptions and characteristics of the adopted methods. The results obtained by the DEM-CFD coupled approach are compared to those published in the literature and those presented by Crosta et al. (Landslide spreading, impulse waves and modelling of the Vajont rockslide. Rock mechanics, 2014) in a companion paper obtained through an ALE-FEM method. Analyses performed along two cross sections are representative of the limit conditions of the eastern and western slope sectors. The max rockslide average velocity and the water wave velocity reach ca. 22 and 20 m/s, respectively. The maximum computed run up amounts to ca. 120 and 170 m for the eastern and western lobe cross sections, respectively. These values are reasonably similar to those recorded during the event (i.e. ca. 130 and 190 m, respectively). Therefore, the overall study lays out a possible DEM-CFD framework for the modelling of the generation of the hydrodynamic wave due to the impact of a rapid moving rockslide or rock-debris avalanche.

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Numerical modeling of 2‐D granular step collapse on erodible and nonerodible surface

Cited by 123 publications

References 50 publications

Frictional velocity-weakening in landslides on Earth and on other planetary bodies

Frictional velocity-weakening in landslides on Earth and on other planetary bodies

The role of constitutive models in MPM simulations of granular column collapses

Rockslide and Impulse Wave Modelling in the Vajont Reservoir by DEM-CFD Analyses

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