A NEW NUMERICAL MODELLING APPROACH FOR FLEXIBLE ROCKFALL PROTECTION BARRIERS BASED ON FAILURE MODES

To study the mechanical behaviour of the flexible rockfall protection barriers under impact load, four full-scale impact tests involving protection capacities of 750 kJ and 2000 kJ were conducted, including two successful and two failed tests. The experimental results show that the system has three working stages. Among these three stages, the second and the third stages play significant roles in both absorbing the impact energy and ensuring the system performance reasonable. Based on the observed failure modes in the tests, the key factors leading to the breakdown of the system are investigated. A new numerical modelling approach is established, which is able not only to predict the capacity of the flexible protection barrier subjected to the rockfall impact but also to accurately simulate the main failure modes such as buckling of the steel post and breakage of the rope. The experimental results are employed to assess and verify the calculation model, and the numerical responses of the system are in good agreement with the test data. Furthermore, a flexible rockfall protection barrier with a capacity of 5000 kJ is designed by using the numerical procedure as an effective tool, shown by a full-scale impact test.