Structures in mountainous areas need to be protected against rockfall hazard to prevent possible fatal damages. In recent years, a new type of rock fence constructed of concrete-filled steel posts, wire ropes, and wire netting has been developing in Japan. To verify the performance of this rock fence, dynamic finite element analysis based on numerical models of two full-scale collision tests was conducted. The performance of energy absorbers, which are effective in preventing wire ropes from breaking, was investigated with respect to their configuration and corresponding energy-dissipation behavior. In numerical simulation, a commercial finite element code featuring explicit dynamic capabilities was employed. The numerical results were compared with experimental data and good agreement was recognized in both cases. The results of numerical simulation have highlighted limitations of the testing method. In other words, the numerical results have provided a deeper understanding of the structural behavior and functions of individual components of the rock fence during rockfall impact. More importantly, numerical simulations can be used as supplements to or substitutes for full-scale tests, particularly in parametric studies and in design and redesign work.

The imperative need to protect structures in mountainous areas against rockfall has led to the development of various protection methods. This study introduces a new type of rockfall protection fence made of posts, wire ropes, wire netting and energy absorbers. The performance of this rock fence was verified in both experiments and dynamic finite element analysis. In collision tests, a reinforced-concrete block rolled down a natural slope and struck the rock fence at the end of the slope. A specialized system of measuring instruments was employed to accurately measure the acceleration of the block without cable connection. In particular, the performance of two energy absorbers, which contribute also to preventing wire ropes from breaking, was investigated to determine the best energy absorber. In numerical simulation, a commercial finite element code having explicit dynamic capabilities was employed to create models of the two full-scale tests. To facilitate simulation, certain simplifying assumptions for mechanical data of each individual component of the rock fence and geometrical data of the model were adopted. Good agreement between numerical simulation and experimental data validated the numerical simulation. Furthermore, the results of numerical simulation helped highlight limitations of the testing method. The results of numerical simulation thus provide a deeper understanding of the structural behavior of individual components of the rock fence during rockfall impact. More importantly, numerical simulations can be used not only as supplements to or substitutes for full-scale tests but also in parametric study and design.

To protect existing structures in mountainous areas against rockfall, various protection methods have been developed. A new type of rockfall protection fence is constructed of posts, wire ropes, and wire netting. To verify the performance of this rock fence, both experiments and numerical analysis based on finite element code were conducted. Collision tests were performed, in which a reinforced-concrete block rolled down a natural slope and struck the rock fence at the end of the slope. The performance of energy absorbers, which are effective in preventing wire ropes from breaking, was investigated. To measure the acceleration of a reinforced-concrete block rolling down a steep slope, a new system of measuring instruments was developed.