Effect of boulder shape on the response of compound meshes subject to dynamic impacts

Rockfall is a type of natural hazard associated with the detachment of one or several boulders in steep slopes. Passive risk mitigation strategies are based on intercepting these blocks during their movement, using rigid barriers, embankments, and flexible protection systems. In recent years, the advancement of remote sensing techniques based on discrete fracture networks allows the characterisation of the shape and size of these boulders even before their detachment [13]. However, physical and numerical modelling of the impact on flexible protection system typically considers spheres [4] and truncated cubes [3] as boulder shape. In this work, the local, i.e. bullet effect [5] and full-scale effect of the aspect ratio of the block is investigated during its impact with a full-scale barrier model. The barrier is characterised by a compound mesh, formed by interweaved double-twisted hexagons and strand ropes stretched between two fence posts. The mesh geometry is reproduced within the Discrete Element framework, using the remote contact interaction approach and the fast mesh generation technique described in [11].