DAMAGE MECHANISM OF ROCKFALL BARRIERS UNDER STRONG IMPACT LOADING

To study the mechanical behavior of rockfall barriers under the effect of rockfall impact, statistics and studies of the system failure characteristics were carried out based on the survey of actual projects. Working mechanisms of the main structure components were analyzed and mechanical models were built. Impact tests of 5 full scale models ranging from 750 kJ to 5000 kJ were carried out. The failure mechanism, mechanism of force-transfering and deformation, principle of energy consumption were emphatically analyzed in combination with the tests and numerical simulations. Damage evolution mechanism and failure mode of barriers were revealed. The results showed that the impact mechanical behavior of the barriers had three stages of evolution under the impact of rockfall. The main energy dissipation of the system was constituted by the second and third stages, and the last two stages had decisive effects on the performance of the system. The mechanical properties of the barriers were similar to tensegrity systems at macro level, but barriers had the characteristic of self-adaptive variable tension obviously, and it was restricted with the third stage of the evolution. The supporting structure, interception structure and arrangement of the ropes were the main factors to decide the performance of the barriers. Improper system configurations might trigger destruction of the barriers such as buckling of the steel column, breakdown of the intercepting net, breakage of the rope and so on. At last, a new type of high-performance barriers which had a higher capacity of rockfall interception was put forward. The research results could provide theoretical guidance for the design of rockfall barriers.