Dynamic response characteristics of a rock slope under blasting excavation

摘要

It is necessary to study the dynamic response of particles under blasting excavation to ensure the safety of slope. Based on field blasting vibration monitoring experiments, the wavelet packet transforms and numerical calculations were used jointly to study the energy response of particles in a slope at different frequency bands and the dynamic response characteristics of key positions of the benches. The results indicated that the blasting vibration energy in a rock slope would change in different frequency bands. The energy attenuation and amplification effects were mainly manifest as high-frequency energy attenuation and low-frequency energy amplification, respectively. The peak particle velocity (PPV), energy, and peak stress of the slope surface are generally attenuated with the increase in the explosion source distance. The vibration energy in the 51-100Hz frequency band had the greatest attenuation, and the PPV of the vertical component was larger than that of the horizontal component. As the elevation increased, the vibration energy at the top of the bench had the largest amplification coefficient in the 11-25Hz frequency band. Both the particle stress concentration at the bottom of the bench and the "whiplash effect" of the PPV at the top of the bench may affect the stability of slope. Thus, the safety and stability of rock slopes should not be evaluated by only considering a single index, but it should be combined with a comprehensive analysis of multiple indices.