Advances in Science and Technology Vol. 171

Abstract: In Japan, many rockfall protection structures have been constructed in the mountainous areas and along coastlines to protect transportation networks and human lives from falling rocks. The conventional rockfall protection fence which is one kind of these structures, is made by combining with H-shaped steel posts, wire ropes, diamond-shaped wire mesh, and clearance-keeping strips. Absorbing energy for design is relatively small; approximately 50 to 100 kJ, depending on height and length of the fence. To investigate impact-resistance behavior and protective performance of the fence, the authors conducted impact loading tests and 3D elastoplastic impact response analyses for a 2 m high fence. On the other hand, depending on slope and rockfall risk, fences with a height of 2 m or more may be needed. However, impact-resistance behavior of these fences has not yet been fully understood. From this point of view, in order to investigate these impact-resistance behaviors and protective performance, an impact loading test and 3D elasto-plastic impact response analysis were conducted for a conventional rockfall protection fence with 4 m height. Impact loading test was carried out by lifting a steel weight suspended by a truck crane to a predetermined height and subsequently releasing it to collide with the center of the fence through pendulum motion. The measuring items are the impact force, the horizontal displacement of the weight, and the applied force to the wire rope, respectively. The results obtained from this study are: 1) it is experimentally confirmed that the steel weight can be captured by fence; and 2) although the impact-resistance behavior of the fence when the weight passing through the ropes cannot be precisely simulated, the behavior of the fence can be accurately simulated by using the proposed numerical analysis method up to the time of the weight slipping from the ropes.