Design Methodology and Performance Evaluation of High Energy Absorbing Rockfall Protection Net by Full-Scale Experiments and Dynamic Analysis

Abstract

It is obligatory to verify the performance of high-energy-absorbing pocket-type rockfall protection nets by full-scale experiments. While the performance verification by full-scale experiments can provide a practical evaluation, it requires a lot of cost and time because it is necessary to conduct the experiments under several conditions depending on the structure of the rockfall protection net. Therefore, the performance verification by combining full-scale experiments and numerical analysis may be a useful tool. In this study, a full-scale experiment of a high-energy-absorbing pocket-type rockfall protection net was conducted to evaluate the net performance with respect to the required capability, and reusability and repairability of the components by understanding the behavior of the net under the action of heavy weights. Throughout the experiment, the deformation of the net, the change of the wire rope tension with time, and the displacement of the top of the net and the top of the pillar were measured in detail. Moreover, it was confirmed that it is possible to evaluate the performance verification based on the performance requirements. Then, the full-scale experiment was replicated by numerical simulations to examine the effects of the rock shape on the behavior and performance of the simulated net. Through the thorough investigations on the deformation of the net, the relation between the maximum tension of the wire rope and the slip length of the shock absorber, the temporal change of the tension of each wire rope, and the absorbed energy of each structural member, it was judged that the reproducibility of the model predictions is adequately high. Specifically, when the impact energy is constant, the effect of the rock shape on the behavior and performance is considered to be small.

Keywords

• high energy absorbing rockfall protection net
• full-scale experiment
• dynamic analysis
• performance evaluation