Research on blasting damage to tunnel surrounding rock based on acoustic full waveform signal analysis

In order to study the application of Acoustic Full Waveform Signal analysis in blasting damage to tunnel surrounding rock, a formula for blasting damage increment considering cumulative effects was proposed by analyzing the Acoustic Full Waveform Signal before and after blasting, based on the concepts of elastic waves and damage degree. This formula allows the cumulative damage law of surrounding rock blasting to be calculated and analyzed. Furthermore, by introducing the Lorentz curve, Gini coefficient, and fractal theory, and combining them with the surrounding rock blasting damage law, their practicality in studying blasting damage was verified. By combining the change in the dominant frequency and amplitude of the Acoustic Full Waveform Signal before and after rock blasting, the variation law in the frequency domain was obtained and confirmed using the wavelet packet energy spectrum. The results showed that blasting damage intensified with the increase in the number of blasts, but the damage increment gradually decreased. The corresponding signal time-frequency characteristics were marked by the reduction of acoustic wave speed and amplitude, the shift of the main frequency and energy to lower frequencies, and the gradual decrease in the main frequency amplitude.