Analysis of blasting vibration responses in the ramp section of the Beishan Underground Research Laboratory

The Beishan Underground Research Laboratory serves as a crucial experimental platform for the geological disposal of high-level radioactive waste in China. To investigate the impact of blasting vibrations generated by the drill and blast method on the ramp entrance section of the laboratory, the blasting vibration signals of the ramp entrance section were analysed, and the distribution characteristics of the vibration velocity and dominant frequency were obtained. By using the wavelet packet transform, the velocity and energy features within the frequency band of the blasting vibration signals were successfully extracted. The calculation formulas for explosive vibration velocity and dominant frequency were derived and verified utilizing dimensional analysis, in accordance with the Equivalent Elastic Boundary theory. The results show that the vibration velocity is highest at the floor of the ramp, lowest at the roof, and intermediate at the sidewall. Variations in the direction of the vibration velocity were also observed at these locations. The blast vibration frequencies at each location are concentrated in the range of 0∼300 Hz, within which the blast vibration velocity and energy tend to decrease from the floor to the roof. However, an increasing trend is observed in some frequency bands within 100 Hz, which requires attention. The derived formulas for the blasting vibration velocity and dominant frequency, except for the calculation deviation of the dominant frequency at the sidewall, have high accuracy, with a R²>0.8. The calculation error of the dominant frequency at the sidewall may be due to the differences in rock mass vibration stiffness, which requires further verification. These research findings provide important guidance for the field construction of the Beishan Underground Research Laboratory and offer valuable references for similar projects in the future.