Experimentally gained parameters, decisive for rock fall analysis

Azzoni, A.; Freitas, M. H. de

doi:10.1007/bf01020064

Cited by 140 publications

(70 citation statements)

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“…However, as mentioned by several authors (e.g. Azimi et al, 1982;Falcetta, 1985;Bozzolo and Pamini, 1986;Hungr and Evans, 1988;Barbieri et al, 1988;Giani, 1992;Azzoni and Freitas, 1995;Gerber, 1995;Dorren et al, 2006) who have experienced natural and/or artificial in situ rockfalls, the analysis of impacts shows that the characteristics of motion after impact are affected not only by the slope characteristics (including the forest), but also by several parameters related to the block as well as to the kinematics during impact (Table 1).…”

Section: /28mentioning

confidence: 89%

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Half-scale experimental study of rockfall impacts on sandy slopes

Labiouse

Heidenreich

2009

Nat. Hazards Earth Syst. Sci.

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Abstract. In the framework of rockfall trajectory modelling, the bouncing phenomenon occurring when a rock block impacts with the slope surface is the most difficult to predict, owing to its complexity and its very limited understanding. To date, the rebound is commonly quantified by means of two coefficients of restitution estimated from a rough description of the ground material. To acquire a better knowledge of the bouncing phenomenon and to investigate the influence of various impact parameters, a comprehensive experimental study was undertaken at the LMR-EPFL (Rock Mechanics Laboratory -Swiss Federal Institute of Technology Lausanne).After a summary of the main conclusions drawn from a small-scale study, the paper focuses on half-scale experiments, describing first the testing device and the data processing and analysing then the influence of several impact parameters. It is observed that the rebound and the commonlyused coefficients of restitution expressed for the mass centre of the block depend not only on slope material characteristics, but also on factors related to the kinematics (slope inclination and impact velocity) and to the block (weight, size and shape). As many trajectory computer codes consider constant coefficients of restitution only function of the outcropping material, the trajectory results should be interpreted with caution and always checked against field observations.

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Section: /28mentioning

confidence: 89%

“…Wu, 1985;Hungr and Evans, 1988;Pfeiffer and Bowen, 1989;Giani, 1992;Azzoni and Freitas, 1995;Stevens, 1998). The most commonly used definitions are expressed in terms of restitution for velocities or energies, indicating the amount of velocity or energy dissipated during the ground impact ( Fig.…”

Section: Introductionmentioning

confidence: 99%

Half-scale experimental study of rockfall impacts on sandy slopes

Labiouse

Heidenreich

2009

Nat. Hazards Earth Syst. Sci.

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“…Kharaz et al, 2001). Parameter values for various surface types are retrieved from the literature (e.g., Azzoni and de Freitas, 1995;Chau et al, 2002;Schweigl et al, 2003;Heidenreich, 2004).…”

Section: The Rockfall Modelmentioning

confidence: 99%

“…Also the tree hit module was disengaged because no tree hits occurred along the trajectories. Quantitative coefficients of restitution were assigned to each mapped surface cover type along the trajectories using information from in situ field tests on representative ground materials from the literature Azzoni and de Freitas, 1995;Schweigl et al, 2003;Heidenreich, 2004). Due to missing information about the exact starting conditions all trajectories were initiated in rolling mode with a velocity of 1 ms −1 .…”

Section: -D Trajectories In Steg and Bad Ischlmentioning

confidence: 99%

“…The coefficients of restitution for each surface type from the Vaujany test sites were extracted from the literature (e.g., Azzoni and de Freitas, 1995;Chau et al, 2002;Schweigl et al, 2003;Heidenreich, 2004) (Table 1). To mimic the release of the rocks from the shovel of the excavator in the simulations the rocks were started from a height of 1.5 m above ground with a speed of 3 ms −1 and an angle of −30 • (relative to the horizon).…”

Section: Model Validation 241 Test Site Vaujanymentioning

confidence: 99%

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Evaluation of a 3-D rockfall module within a forest patch model

Rammer

Brauner

Dorren

et al. 2010

Nat. Hazards Earth Syst. Sci.

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Abstract. Many slopes in the Alps are prone to rockfall and forests play a vital role in protecting objects such as (rail) roads and infrastructure against rockfall. Decision support tools are required to assess rockfall processes and to quantify the rockfall protection effect of forest stands. This paper presents results of an iterative sequence of tests and improvements of a coupled rockfall and forest dynamics model with focus on the rockfall module. As evaluation data a real-size rockfall experiment in the French Alps and two 2-D rockfall trajectories from Austria and Switzerland were used. Modification of the rebound algorithm and the inclusion of an algorithm accounting for the sudden halt of falling rocks due to surface roughness greatly improved the correspondence between simulated and observed key rockfall variables like run-out distances, rebound heights and jump lengths for the real-size rockfall experiment. Moreover, the observed jump lengths and run-out distances of the 2-D trajectories were well within the stochastic range of variation yielded by the simulations. Based on evaluation results it is concluded that the rockfall model can be employed to assess the protective effect of forest vegetation.

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Rockfall Dynamics: A Critical Review of Collision and Rebound Models

Bourrier¹,

Hungr

2013

Rockfall Engineering

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Experimentally gained parameters, decisive for rock fall analysis

Cited by 140 publications

References 1 publication

Half-scale experimental study of rockfall impacts on sandy slopes

Half-scale experimental study of rockfall impacts on sandy slopes

Evaluation of a 3-D rockfall module within a forest patch model

Rockfall Dynamics: A Critical Review of Collision and Rebound Models

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