Abstract:

According to blasting vibration live data that have been collected, the time-frequency characteristics analysis for blasting vibration signals has made by wavelet packet analysis technology. According to the multi-resolution decomposition of wavelet packet transform, the wavelet packet frequency band energy has been deduced on different bands of blasting vibration signals; and it can reflect the total influence of all the three key elements (intensity, frequency and duration of vibration) of blasting vibration. Energy distributions for different frequency bands of blasting vibration signals are obtained based on wavelet packet energy spectra. Based on the characteristics of dynamic response from the controlled structures by blasting vibration, it is firstly established that a multi-factors blasting vibration safety criterion called response energy criterion. The criterion can reflect the total influence of the intensity, frequency and duration of vibration and the characteristics (natural frequency and damping ratio) of dynamic response from the controlled structures themselves; and the feasibility and reliability of the criterion are validated by the instances. Compared with velocity-frequency safety criterion, this criterion can describe accurately the degree of effect on the controlled structures by blasting vibration, and evaluate more comprehensively blasting seismic effect on the structures.

Key words: blasting seismic effect, wavelet packet transform, response energy, safety criterion