Numerical modelling of entrainment/deposition in rock and debris-avalanches

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

doi:10.1016/j.enggeo.2008.10.004

Cited by 162 publications

(104 citation statements)

References 34 publications

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“…This could lead to a depth-averaged model, which has until now seemed inaccessible because of the dependency on the third normal derivative in the differential Equation (8). Thickness profile in experiments Figure 17.…”

Section: Discussionmentioning

confidence: 99%

A Free Interface Model for Static/Flowing Dynamics in Thin-Layer Flows of Granular Materials with Yield: Simple Shear Simulations and Comparison with Experiments

et al. 2017

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Flows of dense granular materials comprise regions where the material is flowing, and regions where it is static. Describing the dynamics of the interface between these two regions is a key issue to understanding the erosion and deposition processes in natural environments. A free interface simplified model for non-averaged thin-layer flows of granular materials has been previously proposed by the authors. It is a coordinate-decoupled (separated variables) version of a model derived by asymptotic expansion from an incompressible viscoplastic model with Drucker-Prager yield stress. The free interface model describes the evolution of the velocity profile as well as the position of the transition between static and flowing material. It is formulated using the coordinate Z in the direction normal to the topography and contains a source term that represents the opposite of the net force acting on the flow, including gravity, pressure gradient, and internal friction. In this paper we introduce two numerical methods to deal with the particular formulation of this model with a free interface. They are used to evaluate the respective role of yield and viscosity for the case of a constant source term, which corresponds to simple shear viscoplastic flows. Both the analytical solution of the inviscid model and the numerical solution of the viscous model (with a constant viscosity or the variable viscosity of the µ(I) rheology) are compared with experimental data. Although the model does not describe variations in the flow direction, it reproduces the essential features of granular flow experiments over an inclined static layer of grains, including the stopping time and the erosion of the initial static bed, which is shown to be closely related to the viscosity for the simple shear case.

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Section: Discussionmentioning

confidence: 99%

A Free Interface Model for Static/Flowing Dynamics in Thin-Layer Flows of Granular Materials with Yield: Simple Shear Simulations and Comparison with Experiments

et al. 2017

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“…Different approaches to simulating material entrainment have been proposed, ranging from empirical methods that require the input of user-prescribed volume growth rates (e.g., McDougall and Hungr 2005;Chen et al 2006) to process-based methods that simulate entrainment as a function of basal shear stress conditions (e.g., Crosta et al 2009;Iverson 2012). Rheology changes along the path can accompany entrainment and are also important to consider.…”

Section: Numerical Modelsmentioning

confidence: 99%

2014 Canadian Geotechnical Colloquium: Landslide runout analysis — current practice and challenges

McDougall

2017

Can. Geotech. J.

181

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Flow-like landslides, such as debris flows and rock avalanches, travel at extremely rapid velocities and can impact large areas far from their source. When hazards like these are identified, runout analyses are often needed to delineate potential inundation areas, estimate risks, and design mitigation structures. A variety of tools and methods have been developed for these purposes, ranging from simple empirical-statistical correlations to advanced three-dimensional computer models. This paper provides an overview of the tools and methods that are currently available and discusses some of the main challenges that are currently being addressed by researchers, including the need for better guidance in the selection of model input parameter values, the challenge of translating model results into vulnerability estimates, the problem with too much initial spreading in the simulation of certain types of landslides, the challenge of accounting for sudden channel obstructions in the simulation of debris flows, and the sensitivity of models to topographic resolution and filtering methods.Key words: landslides, runout analysis, modelling, risk assessment.Résumé : Les coulées, comme les glissements de terrain tels que les coulées de débris et des avalanches de roches se déplacent à des vitesses extrêmement rapides et peuvent avoir un impact sur de grandes zones, loin de leur source. Lorsque ces risques sont identifiés, les analyses du battement sont souvent nécessaires pour délimiter les zones inondables, estimer les risques et concevoir des structures d'atténuation. Une variété d'outils et de méthodes ont été élaborés pour ces fins, allant de simples corrélations empiriques-statistiques avancées de modèles informatiques en trois dimensions. Cet article donne un aperçu des outils et des méthodes qui sont actuellement disponibles et examine certains des principaux défis qui sont actuellement traités par les chercheurs, y compris le besoin d'une meilleure orientation pour la sélection des valeurs des paramètres d'entrée du modèle, le défi de traduire les résultats des modèles en estimations de vulnérabilité, le problème de la trop grande dispersion initiale dans la simulation de certains types de glissements de terrain, le défi de comptabilité pour les obstacles soudains de canal dans la simulation des écoulements de débris, et la sensibilité des modèles à la résolution topographique et les méthodes de filtrage. [Traduit par la Rédaction]

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“…Therefore, the challenge in dynamic run-out modeling of debris flows is to include the entrainment because models that use a constant volume during the motion of the flow ignore this process and are therefore not able to accurately forecast the characteristics of debris flows with high entrainment rates (Quan Luna et al, 2012). This especially applies to channelized debris flows occurring in heterogeneous torrential watersheds that are characterized by various geological settings and superficial surface deposits (Crosta et al, 2009).…”

Section: H Y Hussin Et Al: Parameterization Of a Numerical 2-d Debmentioning

confidence: 99%

“…A considerable number of approaches have been developed to predict the run-out of debris flows, which can be generally divided into three different groups: empiricalstatistical methods (Hsu, 1978;Corominas, 1996;Rickenmann, 1999), analytical methods (Sassa, 1988;Hungr, 1995;Hürlimann et al, 2007) and numerical methods (Denlinger and Iverson, 2004;Crosta et al, 2009;Hungr and McDougall, 2009). The numerical methods have the strong advantage of being able to calculate the movement of the flow over irregular topographic terrains.…”

Section: H Y Hussin Et Al: Parameterization Of a Numerical 2-d Debmentioning

confidence: 99%

Parameterization of a numerical 2-D debris flow model with entrainment: a case study of the Faucon catchment, Southern French Alps

Hussin

Luna

Westen

et al. 2012

Nat. Hazards Earth Syst. Sci.

100

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Abstract. The occurrence of debris flows has been recorded for more than a century in the European Alps, accounting for the risk to settlements and other human infrastructure that have led to death, building damage and traffic disruptions. One of the difficulties in the quantitative hazard assessment of debris flows is estimating the run-out behavior, which includes the run-out distance and the related hazard intensities like the height and velocity of a debris flow. In addition, as observed in the French Alps, the process of entrainment of material during the run-out can be 10-50 times in volume with respect to the initially mobilized mass triggered at the source area. The entrainment process is evidently an important factor that can further determine the magnitude and intensity of debris flows. Research on numerical modeling of debris flow entrainment is still ongoing and involves some difficulties. This is partly due to our lack of knowledge of the actual process of the uptake and incorporation of material and due the effect of entrainment on the final behavior of a debris flow. Therefore, it is important to model the effects of this key erosional process on the formation of runouts and related intensities. In this study we analyzed a debris flow with high entrainment rates that occurred in 2003 at the Faucon catchment in the Barcelonnette Basin (Southern French Alps). The historic event was back-analyzed using the Voellmy rheology and an entrainment model imbedded in the RAMMS 2-D numerical modeling software. A sensitivity analysis of the rheological and entrainment parameters was carried out and the effects of modeling with entrainment on the debris flow run-out, height and velocity were assessed.

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Numerical modelling of entrainment/deposition in rock and debris-avalanches

Cited by 162 publications

References 34 publications

A Free Interface Model for Static/Flowing Dynamics in Thin-Layer Flows of Granular Materials with Yield: Simple Shear Simulations and Comparison with Experiments

A Free Interface Model for Static/Flowing Dynamics in Thin-Layer Flows of Granular Materials with Yield: Simple Shear Simulations and Comparison with Experiments

2014 Canadian Geotechnical Colloquium: Landslide runout analysis — current practice and challenges

Parameterization of a numerical 2-D debris flow model with entrainment: a case study of the Faucon catchment, Southern French Alps

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