Stability Analysis of Blasting Excavation for High Rock Slope of Highway Reconstruction and Expansion

To analyze the stability of high rock slopes under millisecond blasting in the paper, time-history curves of millisecond blasting dynamic loads are established based on field data from the reconstruction and extension project of the Beijing-Shanghai Highway. Numerical simulations and field monitoring data are used to study the dynamic response characteristics of the slope stress, displacement, velocity, and safety factor at different times. The results show that the local shear stress near the blasting area is greater than the shear strength of the rock mass, which has a good effect on precracking. Additionally, the peak vibration law of the particles near the blasting area is found to change synchronously with the application of the dynamic blast load; as the distance increases, the law gradually weakens and peak vibration occurs only near the maximum value. Moreover, the safety factor of the slope exhibits a decreasing periodic variation. When the dynamic blast load F reaches the maximum load F-max and 0.6 F-max, the corresponding safety factor reaches the minimum load.