In-situ experiment of guided flexible protection system against rockfall on high and steep slope based on the active energy dissipating mechanism

A guided flexible protection system with active energy dissipation is proposed for rockfall protection on the high and steep slope. An equation for active energy dissipation control of the system is established, and the principle of energy dissipation control of the system is clarified, through the analysis of the kinetic energy characteristics of the whole rockfall motion path. Then the technical protection measures are put forward, and the structural model of the system is designed. The in-situ experiment is carried out on a high and steep slope with broken rocks. Test model with 2500kJ protection energy is 130m wide and 82m high, and the longitudinal slope is about 60°. Three kinds of impactors are released from the top of the slope in two conditions: with and without the system on the slope. Compared with the non-protected condition, the results of protected condition are quite positive: the falling time of the impactor extends by 80%; the number of collisions increases about 5 times; the maximum bounce height and lateral offset of the rockfall trajectory are decreased by 80% and 50%, respectively; both the residual kinetic energy and the escaping distance at the bottom of the slope are reduced by 65%; and the energy dissipation rate of the protection process is 89%. With the new system, the comprehensive control of intercept-suppression-guidance of rockfall collapse disaster can be achieved. © 2021, Editorial Office of China Civil Engineering Journal. All right reserved.