Toward objective rockfall trajectory simulation using a stochastic impact model

Abstract

The accuracy of rockfall trajectory simulations depends to a large extent on the calculation of the rebound of falling boulders on different parts of a slope where rockfalls could occur. The models commonly used for rebound calculation are based on restitution coefficients, which can only be calibrated subjectively in the field. To come up with a robust and objective procedure for rebound calculation, a stochastic impact model associated with an objective field data collection method was developed and tested in this study. The aims of this work were to assess the adequacy of this approach and to evaluate the minimum amount of field data required to obtain simulation results with a satisfactory level of predictability. To achieve these objectives, the rebound calculation procedure developed was integrated into a three-dimensional rockfall simulation model, and the simulated results were compared with those obtained from field rockfall experiments. For rocky slopes, the simulations satisfactorily predict the experimental results. This approach is advantageous because it combines precise modelling of the mechanisms involved in the rebound and of their related variability with an objective field data collection procedure which basically only requires collecting the mean size of soil rocks. The approach proposed in this study therefore constitutes an excellent basis for the objective probabilistic assessment of rockfall hazard

Bayesian stochastic modeling of a spherical rock bouncing on a coarse soil

“…It is important to note that the relevance of the numerical model has been proved by comparing its results to the available literature (Bourrier et al, 2008a) and to half-scale experiments of impacts on a coarse soil (Bourrier et al, 2008b). In particular, the impact model was calibrated and validated using laboratory experiments of the impact of a 10-cm spherical rock on a coarse soil composed of gravels ranging from 1 cm to 5 cm (Bourrier et al, 2008b(Bourrier et al, , 2009). The incident velocity of the projectile was 6 m/s and the incident angle could reach values from 0 • to 75 • .…”

StoneNode: A low-power sensor device for induced rockfall experiments

“…There are several simulation programs and rockfall models available, such as the Colorado Rockfall Simulation Program [14], Rockyfor3D [18], RocFall [19], and RAMMS::ROCKFALL [10], [11]. The last one is built around the well-established Rapid Mass Movement Simulation (RAMMS) for avalanches and debris flow and provides the current state-of-the-art 3D rigid body and slippage model, capable of simulating various complex rock shapes and modeling the impact of terrain scaring to provide highly accurate estimates of trajectory probability and potential range.…”

Improving the Integration of Coppice Forest Protection in Rockfall Model

“…Les valeurs basses et hautes des gammes de variation des paramètres d'entrée ont été dé nies pour être représentatives des conditions rencontrées sur le terrain pour di érentes espèces d'arbre , Bourrier et al, 2009, Niklas and Spatz, 2010, CIRAD, 2012. Peu de valeurs de K root sont disponibles dans la littérature, notamment pour le hêtre.…”

“…Plusieurs expérimentations ont été réalisées au cours de ces dernières années [Dorren et al, 2006, Bourrier et al, 2009. Elles permettraient de tester la pertinence de la loi de contact utilisée pour prédire la propagation de blocs.…”