Application of 3D rockfall impact models for a slope in the historical Belisirma village (Cappadocia) considering block shape and size effects on the design of protection barriers

In this case study, rockfalls occurring in the historical Belisirma village were simulated using lumped-mass (LM) and rigid-body (RB) impact models through commercial software. The two approaches produced markedly different results. In LM models, all blocks are assumed to be very small spherical point masses, and they stopped following their initial impacts, with none reaching the downstream houses in danger. In contrast, since the complex and variable nature of the shapes and sizes of falling rocks was incorporated into RB models, the program successfully captured the previous rockfall paths, enabling highly realistic simulations. This improved predictive accuracy and supported the design of more effective protective barriers. The optimal location, dimensions, and energy capacity for fence barriers were identified by RocFall3 simulations. It was found that a barrier with a 2000-kJ-capacity was sufficient to meet the protection requirements, achieving 99% catching performance. Results from the RB model demonstrated that large, rounded blocks having higher kinetic energies and bounce heights tended to travel longer runout distances. Extruded octagonal shapes exhibited greater lateral dispersion than other shapes. When such blocks were excluded from the analysis, a 1000-kJ-capacity barrier was satisfactory to intercept falling rocks. This case study highlighted how two modeling approaches influenced rockfall simulations and emphasized the importance of using accurate impact models for providing enhanced protection against rockfalls in historical sites.