A simple analytical model for pressure on obstacles induced by snow avalanches

Faug, Thierry; Chanut, Benoit; Beguin, Rémi; Naaïm, Mohamed; Thibert, Emmanuel; Baroudi, Djebar

doi:10.3189/172756410791386481

Cited by 28 publications

(21 citation statements)

References 36 publications

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“…Dimensional analysis has led to the proposal that the Froude number is a natural candidate for describing flow dynamics [ Salm , ; Grigorian , ; Bozhinskiy and Losev , ; Faug et al , ] and thus the drag force has also been expressed as a function of the Froude number:

σ_{n} = \frac{1}{2} C_{d} (Fr) ρ u^{2},

…”

Section: Avalanche Forcesmentioning

confidence: 99%

Dynamics of glide avalanches and snow gliding

Ancey

Bain²

2015

Reviews of Geophysics

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In recent years, due to warmer snow cover, there has been a significant increase in the number of cases of damage caused by gliding snowpacks and glide avalanches. On most occasions, these have been full-depth, wet-snow avalanches, and this led some people to express their surprise: how could low-speed masses of wet snow exert sufficiently high levels of pressure to severely damage engineered structures designed to carry heavy loads? This paper reviews the current state of knowledge about the formation of glide avalanches and the forces exerted on simple structures by a gliding mass of snow. One particular difficulty in reviewing the existing literature on gliding snow and on force calculations is that much of the theoretical and phenomenological analyses were presented in technical reports that date back to the earliest developments of avalanche science in the 1930s. Returning to these primary sources and attempting to put them into a contemporary perspective are vital. A detailed, modern analysis of them shows that the order of magnitude of the forces exerted by gliding snow can indeed be estimated correctly. The precise physical mechanisms remain elusive, however. We comment on the existing approaches in light of the most recent findings about related topics, including the physics of granular and plastic flows, and from field surveys of snow and avalanches (as well as glaciers and debris flows). Methods of calculating the forces exerted by glide avalanches are compared quantitatively on the basis of two case studies. This paper shows that if snow depth and density are known, then certain approaches can indeed predict the forces exerted on simple obstacles in the event of glide avalanches or gliding snow cover.

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σ_{n} = \frac{1}{2} C_{d} (Fr) ρ u^{2},

…”

Section: Avalanche Forcesmentioning

confidence: 99%

Dynamics of glide avalanches and snow gliding

Ancey

Bain²

2015

Reviews of Geophysics

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“…In fact, while the impact of a falling rock on a net can be impulsive and punctual (a time domain of a few milliseconds), the interaction of a debris flow with a flexible barrier is more complex, and few recent studies have been conducted to help to understand the impact dynamics, to develop rigorous and useful guidelines, or to establish new verification criteria (Faug et al, 2009(Faug et al, , 2010Federico and Amoruso, 2009;Hübl et al, 2009;Teufelsbauer et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

Debris flow risk mitigation by the means of rigid and flexible barriers – experimental tests and impact analysis

Canelli

Ferrero

Migliazza

et al. 2012

Nat. Hazards Earth Syst. Sci.

126

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Abstract. The impact of a debris flow on a structure can have disastrous effects because of the enormous destructive potential of this type of phenomenon. Although the introduction of risk mitigation structures such as the Sabo Dam, the filter dam and more recently flexible barriers is usual, there are very few methods that are universally recognized for the safe design of such structures. This study presents the results of experimental tests, conducted with the use of a specifically created flume, in order to obtain detailed knowledge of the mechanical aspects, and to analyze the dynamics of the impact of a debris flow on different types of structures. The analyses of the tests, together with the calculation of the thrust caused by the flow, have made it possible to analyze the dynamics of the impact, which has shown differing effects, on the basis of the type of barrier that has been installed.

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“…Our study clearly points at the shortcoming of the snow engineering classical approach. Attention should be also paid on the following points: (i) the influence of more complex material properties (cohesion, clustering) on the closure equations in order to apprehend more complex granular materials close to natural ones, (ii) the more complex flow and obstacle geometries with possible lateral overflows (see a preliminary attempt in [7]) and (iii) the fluid/structure coupling processes which can influence the force the obstacle is likely to undergo (the wall was fixed and rigid), particularly in the context of force fluctuations (see Fig. 3) which were not tackled within the time-average hydrodynamic approach presented in this paper.…”

Section: Discussion and Conclusion: Contribution To Avalanche Dam Designmentioning

confidence: 99%

Granular forces from steady and avalanche flows on a wall-like obstacle: contribution to avalanche dam design

Faug¹,

Chanut²,

Naaïm³

2011

WIT Transactions on the Built Environment

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The present paper deals with the hydrodynamic force from granular streams overflowing a wall-like obstacle. An analytical continuum model is proposed to derive this force both for steady and unsteady flow conditions. The force derived from the continuum model is successfully compared to the time-averaged force from discrete numerical simulations of free-surface granular flows down an incline and overflowing a wall. A good agreement is found in a large range of slope inclinations from a slow dense regime to a rapid dilute one. The continuum model gives the various contributions of the total force. Application to avalanche dam design is discussed.

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A simple analytical model for pressure on obstacles induced by snow avalanches

Cited by 28 publications

References 36 publications

Dynamics of glide avalanches and snow gliding

Dynamics of glide avalanches and snow gliding

Debris flow risk mitigation by the means of rigid and flexible barriers – experimental tests and impact analysis

Granular forces from steady and avalanche flows on a wall-like obstacle: contribution to avalanche dam design

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