Flow experiments with gravel and blocks at small scale to investigate parameters and mechanisms involved in rock avalanches

Manzella, Irene; Labiouse, V.

doi:10.1016/j.enggeo.2008.11.006

Cited by 98 publications

(61 citation statements)

References 17 publications

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“…The height of the centre of mass before release (h v , as defined by Davies and McSaveney 1999) has not been the object here of a systematic study but has been considered as one of the factors since it changes along with the fall height and it will be used in the following to analyse the data. According to the results of Manzella and Labiouse (2009), some series of tests have been carried out to verify whether the sharp discontinuity at the toe of the slope could have an influence on propagation introducing a slightly curved slope break. For the 45° slope the sharp angular slope break between the two panels has been replaced by a smooth curve as shown in Fig.…”

Section: Methodsmentioning

confidence: 99%

Empirical and analytical analyses of laboratory granular flows to investigate rock avalanche propagation

Manzella

Labiouse

2012

Landslides

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The rights are held by Springer-Verlag Wien.The final publication is available at http://link.springer.com. AbstractLaboratory experiments which consist of releasing dry rigid non-cohesive grains or small bricks on an unconfined chute have been designed to investigate rock avalanche propagation mechanisms and to identify parameters influencing their deposit characteristics. Factors such as volume, fall height, basal friction angle, material used, structure of the material before release, i.e. bricks randomly poured into the reservoir before failure or piled orderly one on top of the other, and type of slope break, i.e. curved or sharp angular, are considered and their influence on apparent friction angle, travel angle of the centre of mass, deposit length and runout is analysed.Results highlight the influence of the structure of the material before release and of the type of transition at the toe of the slope on the mobility of granular avalanches. The more angular and sharp is the slope break, the more shearing (friction) and collisions will develop within the sliding mass as it changes its flow direction, the larger will be the energy dissipation and the shorter will be the travel distance. Shorter runout is also observed when bricks are randomly poured into the reservoir before release compared to when they are piled one on top of the other. In the first case more energy is dissipated all along the flow through friction and collisions within the mass. Back-analysis with a sled block model of experiments with a curved slope break underlines the importance of accounting centripetal acceleration in the modelling of the distance travelled by the centre of mass of a granular mass. This type of model though is not able to assess the spreading of the mass and its total runout because it does not take into account the internal deformation and the transfer of momentum within the mass which, as highlighted by the experimental results, play an important role in the mobility of rock avalanches.

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Section: Methodsmentioning

confidence: 99%

Empirical and analytical analyses of laboratory granular flows to investigate rock avalanche propagation

Manzella

Labiouse

2012

Landslides

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“…The materials needed for experiments (bricks and support), identical to those used at EPFL [38], have been made available to us as part of the European project Alcotra MASSA. The analysis of several rebounds allows optimizing the values of the numerical parameters by using an error function that characterizes the difference between the actual trajectory of the particle, before and after rebound, and the one restored by the numerical model.…”

Section: Contact Law and Calibration Of Parametersmentioning

confidence: 99%

“…To carry out the modeling of the experiments performed at EPFL [38], we have implemented a specific procedure, currently operational in laboratory, to identify the numerical contact parameters. This procedure consists in analyzing the fall and rebound of a single particle on a horizontal plane, using a device consisting of two synchronized high-speed cameras shooting at 1000 fps.…”

Section: Contact Law and Calibration Of Parametersmentioning

confidence: 99%

“…This makes it possible to obtain realistic shapes, to optimize the contact detection algorithm and to minimize the time calculation. The contact model, described in the following section, is tested and validated with laboratory experiments performed at EPFL [38], which consist in the release of an assembly of small bricks on a bi-plane. Then, the model is used to highlight the energy dissipation mechanisms occurring along the slope, especially the influence of the blocks shape (bricks and cubes), the undulation of the slope, and the effect of the slope transition between the two planes.…”

Section: Introductionmentioning

confidence: 99%

“…The experimental characteristics of the deposit zone (i.e. dimensions, position, shape) are measured by an optical technique[38]. Numerically, specific algorithms have been developed to define the geometry of the deposit and some characteristics of the kinematics of the flow (average speed and front velocity of the flow).…”

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confidence: 99%

See 2 more Smart Citations

Influence of the morphology of slope and blocks on the energy dissipations in a rock avalanche

Daudon

Villard

Richefeu

et al. 2014

Comptes Rendus. Mécanique

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Collapse of a two‐dimensional brittle granular column: Implications for understanding dynamic rock fragmentation in a landslide

2015

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International audienceWe investigate numerically the failure, collapse, and flow of a two-dimensional brittlegranular column over a horizontal surface. In our discrete element simulations, we consider a verticalmonolayer of spherical particles that are initially held together by tensile bonds, which can be irreversiblybroken during the collapse. This leads to dynamic fragmentation within the material during the flow.Compared to what happens in the case of a noncohesive granular column, the deposit is much rougher,and the internal stratigraphic structure of the column is not preserved during the collapse. As has beenobserved in natural rockslides, we find that the deposit consists of large blocks laying on a lower layer offine fragments. The influence of the aspect ratio of the column on the runout distance is the same as inthe noncohesive case. Finally, we show that for a given aspect ratio of the column, the runout distance ishigher when the deposit is highly fragmented, which confirms previous hypotheses proposed by Davieset al. (1999)

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Flow experiments with gravel and blocks at small scale to investigate parameters and mechanisms involved in rock avalanches

Cited by 98 publications

References 17 publications

Empirical and analytical analyses of laboratory granular flows to investigate rock avalanche propagation

Empirical and analytical analyses of laboratory granular flows to investigate rock avalanche propagation

Influence of the morphology of slope and blocks on the energy dissipations in a rock avalanche

Collapse of a two‐dimensional brittle granular column: Implications for understanding dynamic rock fragmentation in a landslide

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