Stability Analysis and Reinforcement Protection Technology of High and Steep Dangerous Rocks at the Entrance of Railroad Tunnels
Aimming at the problem of rockfall development of high and steep dangerous rock at the tunnel entrance of Gaojiashan Tunnel of Haoji Railway,which seriouly affect the safety of the line construction and tunnel operation,the point cloud data were obtained by 3D laser scanning technology,and the numerical model of the dangerous rock and tunnel opening were established by using the point cloud data to analyze the motion track of the falling stones of the dangerous rocks and stability of the slope.The targeted prevention and control technology is proposed.The results show that the development type of high steep dangerous rock at the tunnel entrance is mainly falling and dumping types,and the maximum displacement reaches 24 mm.Most of the falling rocks after the destabilization of the dangerous rocks will collide with the exit of the Gaojiashan Tunnel,Baishuichuan Bridge and Xueshou Road.It is carried out to utilize a combination of Initiative protective systems and pad pillar type pressure grouting anchors to reinforce the dangerous rock,and to use reinforced concrete retaining walls and passive protective systems to establish an energy dissipation and speed reduction platform.