Comparison of full-scale rockfall tests with 3D complex-shaped discrete element simulations
Résumé
The analysis of trajectories is often needed to face the rockfall hazards. It is now essential to
rene the understanding of the interactions of falling rock blocks with the terrain, depending on
involved elements. They include the topology and nature of the soil, but also the volume and
shape of the falling blocks. The main objective of this work is to replicate eld observations
using a 3D discrete elements model (DEM) in order to assess unreachable data in experiments.
The model applied implements blocks of realistic shapes that were reconstructed from in situ
blocks, and the dissipation of kinetic energy at the collision point is suitably managed. In the
experimental campaign, dozens of boulder (rock block) releases were conducted on two slope
proles of a quarry located in Authume (France). Block passing heights, velocities and runout
distances were assessed at specic ground points. We analyzed lateral spreads, propagation distances,
and energy balances computed for 3 dierent block geometries. These numerical results
were confronted with experimental observations. The DEM model is ecient and versatile.
It allows to simulate quite accurately a multitude of congurations. Among the multitude of
terrain and block properties, geometric features are shown to be crucial. In spite of this, to
allow the analysis of the experimental data, a deliberately very basic characterization of the
block shape { which is only related to its lengthiness { was chosen for sake of eciency.