Experimental study of the impact response of geocells as components of rockfall protection embankments

Abstract

Abstract. Rockfall protection embankments are ground levees designed to stop falling boulders. This paper investigates the behaviour of geocells to be used as components of these structures. Geocells, or cellular confinement systems, are composite structures associating a manufactured envelope with a granular geomaterial. Single cubic geocells were subjected to the impact resulting from dropping a spherical boulder. The geocells were filled with fine or coarse materials and different boundary conditions were applied on the lateral faces. The response is analysed in terms of the impact force and the force transmitted by the geocell to its rigid base. The influence on the geocell response of both the fill material and the cell boundary conditions is analysed. The aim was to identify the conditions resulting in greatest reduction of the transmitted force and also to provide data for the validation of a specific numerical model.

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

“…Second, deformation should preferably result from irreversible mechanisms leading to energy dissipation. As shown in a previous experimental study (Lambert et al, 2009), crushing is a fundamental phenomenon in the impact response of geocells filled with stones. First, crushing dissipates energy and, second, it limits the stress to a threshold, which depends on the size and crushing resistance of the stones.…”

“…The third stage corresponds to the global structure reverse displacement. This mechanism is mainly attributed to the elasticity of the sand-tyre mixture (Lambert et al, 2009). …”

“…This is particularly important when accelerometers are placed in contact with the crushed limestone fill. Indeed, impact leads to stone displacement and crushing, resulting in very rapid force variations requiring signal smoothing (Lambert et al, 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.…”

Improving the Integration of Coppice Forest Protection in Rockfall Model

“…Les protections dites passives sont mises en place le long des versants avec pour objectif d'arrêter les blocs en mouvement ( lets pare pierres, merlons...) [Lambert et al, 2009, Mignelli et al, 2013.…”