Dynamic rockfall risk assessment using multi-source data fusion and 3D simulation: a case study of Jiaohua rock

Rockfall represents a sudden and highly destructive geological hazard, posing significant risks to mountainous communities and infrastructure. This study presents an integrated dynamic risk assessment for the Jiaohua perilous rock zone in Kaizhou District, Chongqing, China, by fusing multi-source data including field investigation, UAV photogrammetry, and 3D numerical simulation. Kinematic analysis identified a critical slope angle of 57° for rockfall initiation, enabling the classification of two primary susceptibility zones. High-precision 3D simulations using RAMMS: ROCKFALL were conducted on six identified hazardous rock masses (#WY1–#WY6). The simulations delineated two distinct rockfall mechanisms: #WY1–#WY3 sources generate high-energy, short-duration impacts, achieving kinetic energies up to 1.88 × 10⁴ kJ within 10–15 s, posing a direct threat to the residential area below. Conversely, rockfalls from #WY4–#WY6 involve longer travel paths with considerable energy attenuation, yet residual kinetic energy remains capable of causing zonal damage. The simulated kinetic energies were translated into quantitative impact force estimates, forming the basis for differentiated mitigation strategies. These include active reinforcement and high-strength interception for short-range, high-energy events, and multi-level buffering with trajectory control for long-runout cases. This integrated methodology offers a scientifically grounded framework for precise hazard prevention and serves as a valuable reference for rockfall risk management in analogous geological settings, particularly within the Three Gorges Reservoir area.