延时间隔对爆破振动信号时频特征的影响

为探索延时间隔对临近边坡爆破振动峰值速度、主频和信号中的能量分布等影响,在贵州某石灰石露天矿爆破施工现场进行爆破振动测试。采用小波包分析方法对不同延时间隔(25、42、65 ms)的爆破振动信号进行分析研究。结果表明,在相同爆心距条件下采用65 ms延时的爆破振动峰值速度最小,爆破振动信号的能量主要集中在0~62.5 Hz的中低频带,但是不同频带中的能量占比略有差异。随着延时间隔由65 ms减小至25 ms,其0~15.6 Hz频带的能量从54.01%增加至93.33%,15.7~62.5 Hz频带的能量从45.61%减小至6.61%,即随着延时间隔的降低,其爆破振动信号能量往低频带集中,而该频带非常接近边坡的固有频率,对边坡稳定性不利。

The influence of delay interval on time-frequency characteristics of blasting vibration signal

In order to explore the influence of delay interval on the blasting vibration peak,the main frequency and the energy distribution in the signal of the adjacent slope,the blasting vibration test was carried out at the blasting construction site of a limestone open-pit mine in Guizhou.The method of wavelet packet analysis was used to analyze the blasting vibration signals with delay intervals(25,42,65 ms).The results show that the blasting vibration peak value of 65 ms is the smallest under the same core distance.The energy of blasting vibration signal is mainly concentrated in the low and medium frequency band of 0-62.5 Hz,but the energy proportion in different frequency bands is slightly different.With the decrease of the delay interval from 65 ms to 25 ms,the energy of the 0-15.6 Hz frequency band increased from 54.01% to 93.33%,and the energy of the 15.7-62.5 Hz frequency band decreased from 45.61% to 6.61%.So with the decrease of the delay interval,the blasting vibration signal energy is concentrated in the low frequency band,and the frequency is very close to the natural frequency of the slope,which is unfavorable to the stability of the slope.