Investigation on dynamic response of rockfall net fences under irregular block impact

Rockfalls frequently occur in the mountainous area, posing significant risks to public transportation and the safety of people’s lives and property. Rockfall net fences are commonly used to mitigate and prevent rockfall incidents. Through field investigations of blocks within a 100-meter range of rockfall net fences, it is found joint-fractured octahedron takes the majority portion. Numerical model without substitution on ring net is established and validated compared with a conducted full-scale experiment, and dynamic response of rockfall net fence by the octahedral impactors with sphericity values ranging from 0.5 to 0.8 is explored. The results indicated that impactors with sharp shapes produce fewer rings during the impact moment, leading to stress concentration and causing higher stress on rings. It is inferred that design the rockfall protection system with traditional test impactor tend to be more unsafe and may cause localized failure and fence penetration when suffering a sharp block impact even the impact energy is lower than the capacity.