Prediction of characteristic blast-induced vibration frequency during underground excavation by using wavelet transform

Blast-induced vibration produces a very complex signal,and it is very important to work out environmental problems induced by blasting.In this study,blasting vibration signals were measured during underground excavation in carbonaceous shale by using vibration pickup CB-30 and FFT analyzer AD-3523.Then,wavelet analysis on the measured results was carried out to identify frequency bands reflecting changes of blasting vibration parameters such as vibration velocity and energy in different frequency bands.Frequency characteristics are then discussed in view of blast source distance and charge weight per delay.From analysis of results,it can be found that peak velocity and energy of blasting vibration in frequency band of 62.5–125 Hz were larger than ones in other bands,indicating the similarity to characteristics in the distribution band(31–130 Hz)of main vibration frequency.Most frequency bands were affected by blasting source distance,and the frequency band of 0–62.5 Hz reflected the change of charge weight per delay.By presenting a simplified method to predict main vibration frequency,this research may provide significant reference for future blasting engineering.