Movement characteristics and construction control of unstable rock masses on high and steep slopes in highway reconstruction and expansion projects

Unstable rock group of the high and steep slope on the reconstruction highway directly threatens the safety of the Yongtaiwen highway and Yonglin Line, and the possible property losses and casualties are difficult to be estimated. However, the limited construction site and safety requirements make the treatment of the unstable rock group extremely difficult, which is becoming the most prominent engineering geological problem in the reconstruction highway. Based on the spatial morphology analysis of the unstable rock group and the situation of high and steep slopes, once the initiation conditions are met, the unstable rock masses begin to roll down the slope The motion stage is divided into four stages: slope rolling stage, projectile flight stage, bouncing collision stage, and rolling stop stage. The motion and mechanical calculation models of the four stages are derived, and the motion trajectory characteristics of the unstable rock group are simulated and predicted. Important parameters such as bouncing height, motion speed, total energy, and stop position at different positions are obtained. It is proposed to fully utilize the reverse inclined favorable structural plane to adopt a combination of manual excavation and excavator machinery excavation method, and active temporary support and passive protection measures are set up to ensure the safe removal of the unstable rock mass group. This provides a reference case for similar engineering geological problems