The 3rd Badong International Geohazards Symposium (BIGS2021)

59 / 2021-11-15 20:51:21

Research on the energy dissipation mechanism of rockfall impacts on the improved rockfall attenuator barrier

rockfall,impact,in-situ test,numerical simulation

With the main mechanisms of guidance and energy dissipation, the rockfall attenuator barrier has become a flexible structure to control rockfall disaster. The problems of difficult maintenance and high cost hinder the popularization and application of classic rockfall attenuator barriers in the field of rockfall protection. Therefore, combining with the lower open-ended design concept, we optimize the extension length and propose an improved rockfall attenuator barrier. In this study, the energy dissipation mechanism of the improved barrier under the different extension lengths was searched, by carrying out in-situ test of the rockfall impact. The results show that the improved barrier is conducive to cleaning up the rockfall stopped in the mesh. The constraint and friction effect of the improved barrier can effectively exert its flexible energy dissipation characteristics, thus reducing the impact energy of rockfall. When the extension length of improved barrier increases from 3 m to 7 m, the energy attenuation rate of rockfall increases by approximately 20%, however, the increment of energy attenuation decreases gradually. To further improve the energy dissipation effect of the improved barrier, the influence of impact positions and angles of rockfall on the energy dissipation effect of the improved barrier was studied by numerical simulation. The simulation results show that the energy attenuation rate is the highest when rockfall impacts the middle position of the improved barrier, and the energy attenuation rate is increased by 20% compared with the position at the side of the impact edge. The energy attenuation rate of rockfall is the highest and reaching 74.1%, when the angle between impact direction of the rockfall and improved barrier is approximately 45°. Therefore, the energy dissipation effect of the rockfall attenuator barrier could be maximized by setting extension length, installation location and inclination angle reasonably in engineering practice.