Hazard zoning and assessment of rockfalls based on AHP-3DEC

Restricted by the surface smoothness and topography, it is impossible for some high-speed railways on mountainous regions to avoid parts of rockfall development sections, posing great safety challenges to construction projects and railway operations. In light of that, this paper laid its focus on the rockfall situated by the entrance of Xinghuayu Tunnel along the proposed Jinan-Zaozhuang Railway project, and leveraged the power of drone-captured 3D aerial photography to perform digital geological survey and mapping so as to accurately identify the development characteristics, scale, as well as modes of deformation and failure of said rockfall. Next, by cross-referencing the results of 3DEC numerical simulation with those from analytic hierarchy process (AHP), color-coded maps highlighting the scope of influence and danger levels of potential rockfalls induced were obtained. Using said maps, zone-by-zone hazard and risk assessment were then performed, based on which corresponding prevention and control measures were put forward. The findings show that among the 12 dangerous rock belts identified from the drone-captured 3D aerial photography model, only Belt No. 5 would threaten the safety of the tunnel entrance and bridge abutments, for which the combination of anti-rockfall passive protective netting and an open-cut tunnel structure was recommended as a comprehensive solution. By virtue of the solution’s effectiveness, this study can offer reliable references for not only zone-by-zone hazard and risk assessment for rockfalls, but also railway route selection and disaster prevention and mitigation.