Physical modelling of rock fragmentation upon impact

Rockfall represents a significant safety hazard in building, civil and mining environment that can cause serious injuries and fatalities and can damage structures, infrastructure and machinery. It is extremely costly to manage and public authorities need reliable tools to study and design protection structures as the performance of the existing structures are variable. Many studies and experiments have been done, but one aspect would lead to a better comprehension of the subject: the fragmentation of blocks upon impact. Rocks commonly break up upon impact but rockfall prediction models currently available mostly ignore this phenomenon, even though fragmentation changes size, shape and energy of falling blocks and can drastically change the outcome of the design of protective structure. For example, if a large rock breaks upon impact and its mass and energy are divided among fragments, a high level of energy is dissipated and ignoring fragmentation would lead on an overdesign of the protection barrier. Moreover, very fast rock fragments may rupture a rockfall protection. The project aims to overcome this limit, studying and considering fragmentation in rockfall model, allowing assessment of the hazard rising from a shattered rock. The intention is to develop a database of experimental data about fragmentation of blocks upon impact by considering the initial conditions that cause fragmentation, the fragment size and mass distribution, the partition of velocity and energy at impact and what may lead to “bullet effect” or high flying fragment. This project aims to include fragmentation in rockfall prediction causes to facilitate a better and safer mitigation of rockfall hazard. Moreover, a better knowledge will directly translate into economical and societal benefits, such as more cost effective and better user experience.