Safety netting to trap falling rocks
Rock-fall protection and mitigation are key elements in the security and safety of infrastructure or construction developments. For example, even small rock slides or debris flows can block routes and thus initiate far-reaching economic effects well beyond the immediate area of disruption. Reducing the risk of damage from boulders and debris falling from a rock or cliff face was the goal of the 'New concept and technology for high energy rock fall protection fences' (ABSORBNET) project, funded by the EU. Current high-energy protection barriers are based on the Second World War anti-submarine net design. ABSORBNET set out to modernise and improve on this net design, in terms of the materials used and the setup. It aimed to develop a protection net that was capable of absorbing the high energy of moving rocks. The net developed during the project, which has already been patented, is based on an inorganic polymer composite reinforced with carbon nanotubes. This novel composite material can be further processed by gel spinning to manufacture a high-performance fibre. Using a rope configuration, the ABSORBNET team wove the new fibre into a yarn. In order to provide weather protection and reduce resistance, the project formulated and applied a fluoropolymer coating to the yarn. However, the current coating cannot ensure the complete stability of the yarns under a full-weathering ageing test. Therefore, future work will be required to improve the coating's stability during weathering. By interweaving the coated yarns manually, the now completed project was finally able to produce a splice net with a square-shaped mesh. In the future, this novel barrier will also be protected with a patent so that it can be commercially exploited as a high-energy rock-fall protection.