Welch Spectrum Analysis And Safety Assessment Of Deep-hole Blasting Vibration Signals In Mines

Spectrum analysis of blasting vibration signal is the key problem for scientific and in-depth vibration safety assessment.Explosives in deep hole blasting in mines is generally high that can easily lead to blasting hazards.Three field monitoring experiments of blasting vibration signals were carried out in this paper study on deep hole blasting in underground well and open hole blasting.The characteristic parameters and propagation characteristics of blasting vibration signal spectrum were analyzed,and safety evaluation of blasting vibration was carried out.The main research contents and results are as follows:On the basis of expounding the development status of classical power spectrum estimation,Started at the Fourier transform length,the selection of window functions,and the realization of MATLAB simulation,the selection and simulation of the relevant setting parameters of Welch power spectrum estimation were studied comprehensively through theoretical analysis.Based on the Welch power spectrum graph of blasting vibration signal measured in the field,the characteristic parameters of blasting vibration were defined.The main peak characteristics and secondary peak characteristics of the deep hole blasting vibration signal were analyzed of using Welch power spectrum estimation.The research shows that the signal dominant frequency band is 13 ~ 53 Hz,the secondary peak frequency band is 101 ~176 Hz.The farther from the center of explosion source,The main peak span,main frequency ratio,peak PSD,second peak PSD,and secondary peak frequency of the three direction wave-forms of the signal will be weakened.In most cases,the peak PSD of horizontal radial L is relatively high;change of vertical characteristic parameters can reflect general trend of the whole signal.The roadway between measuring point and explosive source has a great influence on the propagation attenuation of the signal.Main peak and secondary peak characteristics of the blasting vibration signal in deep hole of the outdoor steps were analyzed by Welch.The study showed that the dominant frequency band is6 ~ 32 Hz and the secondary peak frequency range is 57 ~ 199 Hz.The farther away from the center of the explosion,Welch feature parameters such as the main peak span,main frequency ratio,peak PSD,second peak PSD,and secondary peak frequency of the three direction wave-forms will show a weakening trend.Based on the statistical data measured,the Saga formula for deep hole blasting in underground mining and open step blasting was obtained by using Mat-lab programming.Theminimum safe distance allowable value of underground deep hole blasting vibration to mine roadway and surface building was calculated,based on the parameter characteristics of Welch spectrum estimation.While the empty mining area needed to be collapsed or cemented and filled with tailing.The blasting vibration had no effect on buildings such as surface houses.The permitted values of the minimum safe distance of the open air deep hole blasting vibration to the Adobe and general civil buildings,and industrial and commercial buildings are 471.95 M,149.82M,and 97m,respectively.