Shaft Blasting Vibration and CO₂ Fracturing Vibration Signals by Wavelet Packet Analysis

In order to understand the hazards of CO₂ fracturing vibration and propose the purpose of the hazard control method, the CO₂ fracturing vibration and blasting vibration signals are studied from the perspective of energy distribution characteristics. In combination with a subway shaft project, vibration signals at specified points in the shaft were obtained, and wavelet packets were used to analyze the vibration signals using db6 wavelet basis. The results showed that the peak particle velocity of CO₂ fracturing was only 10% of the explosive blasting under most conditions. The change of blasting vibration signal energy shows the characteristics of fast decay at high frequency and slow decay at low frequency over time; blasting vibration energy has a wide range of distribution, and the frequency band of CO₂ fracturing vibration energy is more concentrated, the center frequency is about 120 Hz, and the relationship between the vibration energy of the three vector directions is shown as follows: z direction>y direction>x direction.