Modelling a geo-composite cell using discrete analysis

Abstract. The prediction of the effects of rockfall on passive protection structures, such as reinforced ground embankments, is a very complex task and, for this reason, both full-scale tests and numerical dynamic modelling are essential.A systematic set of numerical FEM models, developed in the dynamic field, has been implemented in this work to evaluate the conditions of an embankment that has been subjected to the impact of rock blocks of various sizes at different speeds. These analyses have permitted design charts to be obtained. Furthermore, a simplified analytical approach, based on an equilibrium analysis, has been proposed and its results are compared with numerical data in order to assess its feasibility. A good correspondence between the results has been obtained.

Section: Introductionmentioning

confidence: 99%

Design of reinforced ground embankments used for rockfall protection

Ronco

Oggeri

Peila

2009

“…For instance, experimental and numerical studies at the geocell scale (Bertrand et al, 2005;Lambert et al, 2009Lambert et al, , 2011 and at the scale of an assembly of geocells were conducted (Bourrier et al, 2011;Dimnet el al., 2013;Heymann et al, 2010Heymann et al, , 2011. The experimental facet of this study emphasized instrumentation monitoring, to investigate the structure's response and validate the derived numerical models.…”

Section: Introductionmentioning

confidence: 99%

Real-scale investigation of the kinematic response of a rockfall protection embankment

Lambert¹,

Heymann

Gotteland

et al. 2014

Abstract. This paper addresses the response of rockfall protection embankments when exposed to a rock impact. For this purpose, real-scale impact experiments were conducted with impact energies ranging from 200 to 2200 kJ. The structure was composed of a 4 m high cellular wall leaned against a levee. The wall was a double-layer sandwich made from gabion cages filled with either stones or a sand-schreddedtyre mixture. For the first time, sensors were placed in different locations within the structure to measure real-time accelerations and displacements. The test conditions, measurement methods and results are presented in detail. The structure's response is discussed in a descriptive and phenomenological approach and compared with previous real-scale experiments on other types of embankments.

“…The boulder radius R b varies from R m to 5 R m . The influence of particle shape is also explored by defining two different soil samples composed of either spherical particles or elongated particles modeled by indivisible assemblies of spherical particles called clump particles, which can realistically model the shape of soil rocks (Bertrand et al, 2006;Deluzarche and Cambou, 2006;Bourrier et al, 2008a). The soil sample generation procedure leads to soil porosity values of 0.204 for spherical particles and 0.171 for clump particles.…”

Section: Numerical Modeling Of Impacts Using the Discrete Element Methodsmentioning

confidence: 99%

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

Bourrier¹,

Eckert²,

Nicot³

et al. 2009

Abstract. Trajectory analysis models are increasingly used for rockfall hazard mapping. However, classical approaches only partially account for the variability of the trajectories. In this paper, a general formulation using a Taylor series expansion is proposed for the quantification of the relative importance of the different processes that explain the variability of the reflected velocity vector after bouncing. A stochastic bouncing model is obtained using a statistical analysis of a large numerical data set. Estimation is performed using hierarchical Bayesian modeling schemes. The model introduces information on the coupling of the reflected and incident velocity vectors, which satisfactorily expresses the mechanisms associated with boulder bouncing.The approach proposed is detailed in the case of the impact of a spherical boulder on a coarse soil, with special focus on the influence of soil particles' geometrical configuration near the impact point and kinematic parameters of the rock before bouncing. The results show that a first-order expansion is sufficient for the case studied and emphasize the predominant role of the local soil properties on the reflected velocity vector's variability. The proposed model is compared with classical approaches and the interest for rockfall hazard assessment of reliable stochastic bouncing models in trajectory simulations is illustrated with a simple case study.