Dynamic analysis of rock fall impact for a cantilever rock shed with geofoam cushion

In this study, the effect of geofoam compressible cushions on the impact response of the rockfall protection galleries located in a main artery highway connecting the southern Turkey to central Anatolia is investigated. Due to high occurrence risk of rockfall hazard at the mountainous region, permanent protection structures are required to prevent damage. Numerical analyses were carried out to evaluate the performance of EPS geofoam compressible layers with different stiffness characteristics on reducing the transmissibility of the impact forces caused by rockfalls. The kinetic energy levels, expected fall velocities for rock masses and the typical rockfall paths were assessed considering the topography of the hill. Dynamic explicit finite element analyses were performed to investigate the effect of the rockfall impact on a reinforced concrete rock shed. Stresses, strains and displacements on the structural section and the cushioning zone were monitored through the analyses. Based on the results, it was observed that geofoam has a significant effect on reducing the transmitted forces to the structure while increasing the impact duration. In terms of structural displacements, up to 75% reduction is observed when EPS cushions are placed on top of rock shed structure.