Abstract: A highway on the border between China and Vietnam is faced with severe risk of rockfall from high mountain, and conventional protection scheme is hardly effective.To solve this problem, the movement law of rockfall is analyzed via numerical simulation and protection design scheme is put forward.The conclusions are as follows:1) When the impact energy of rockfall far exceeds the protection capacity of engineering measures, great attention should be paid to slope design to guide the rockfall to move along controllable trajectory and reduce the energy by collision. In this research, the energy attenuation rate of rockfall after collision could reach over 80% by wide platform and rockfall trough. 2) The smaller the angle between the excavation line at the top of the slope and the tangent line of the natural slope, the more conducive it is to guide the falling rock to fall along the slope. 3) Due to complex rockfall movement track, the inward sloping platform can be used together with higher low-energy passive protection net despite its excellent rockfall retention and energy attenuation effect. Wide platform could generate regular rockfall trajectory and low bounce, hence can be used with lower high-energy level passive protection net. 4) Using waste soil as cushion could remarkably improve the effect of rockfall protection and alleviate environmental pollution, and also could beautify the landscape after planting. The research ideas and results provide reference for rockfall protection.

Key words: rockfall, rock avalanche, geological disasters, slope protection, passive protection net