Study On The Collision Effect Of The Rolling Stone To High Hollow Thin-Walled Pier

Because of bad geological conditions, mountain bridges are often influenced by all kinds of geological hazards, especially a serious threat of rolling stone collision to the bridges. In recent years this kind of disaster has repeatedly occurred and caused major bridge damage accidents, this collision problem attracted people's attention. In order to improve the rockfall impact resistant ability and ensure the safety of the mountain bridges during the opera tion time, this paper took a mountain bridge's high hollow thin-walled pier as the research object, simulated the dynamic process of rolling stone collision with bridge pier and analyzed some main factors that influenced the value of displacement and impact force of the pier.In this paper, ANSYS/LS-DYNA simulation was adopted to analyze the parameter settings and dynamic calculation process of the rockfall impact to reinforced concrete bridge piers. According to the validated model parameters, finite element model of Western Mountain hollow thin-walled high pier is established. Through simulation of the collision process, dynamic response of the pier stress nephogram, displacement time history curve, and the impact force curve were obtained. Then different factors(rolling stone's quality, speed, impact position, and the contact area) were simulated to study the destruction, displacement, impact force of the pier to the collision. Finally, the impact force derived from simulation and the theoretical calculations were compared and analyzed to evaluatethe numerical simulation results.Through the numerical simulation and theoretical analysis on the impact effect of the rolling stones to hollow thin-walled high pier, the conclusions of the study were as follows:(1) Through the simulation of the impact test of rockfall to reinforced concrete pier, the conclusion is obtained that numerical simulation method can be used to conducte the study on the bridge pier collision problem by reasonable value.(2) Local damage is the mainly damage form of the impact betwin rolling stone and high hollow thin-walled pier, the affect arae is basicaly in the contact area.(3) With the increase of rolling stone mass and velocity, pier damage form is gradually transformed from bending failure to local damage; Rock impact position had little effect on the impact force, but had significant effect on the pier top displacement; The contact area had great effect on the impact force, so the rolling stone could not be simplified as a particle.(4) The conclusion was obtained through the comparision betwin numerical simulation results and the theoretical calculation results that the trend of the impact force calculated from the two method was the same, and the impact force increased linearly with the rolling stone velocity, but the growth rates were different.