隧道周边孔爆破振动信号分析

为了解周边孔爆破对控制爆破振动速度的影响,以大连玉华220kV线路新建工程2#大里程隧道为例,分析周边孔爆破振动信号。2#大里程隧道临近商业建筑,通过掏槽孔、周边孔两次起爆,达到了控制爆破振速的目的。因此,在爆破断面垂直的商铺附近,距离爆破断面约6m处布置测试点进行监测。采用FFT法、小波包分析法、加速度功率谱密度法对爆破的振动速度、持续时间、主频、能量-频率分布等进行了分析。结果发现:周边孔爆破中距爆破断面水平距离6m处的最大单向振动速度为1.122 4cm/s,频率较高,80Hz以上,在《爆破安全规程》规定的振动速度范围之内。同时分析了3种方法的异同点,FFT法的速度谱与小波包分析的能量-频谱图波形相似,主频与小波包分析法相差不大,与加速度功率谱密度计算的主频非常接近,可用FFT法初步分析爆破振动信号的能量分布比例。小波包分析法在主频确定方面有更高的分辨率,在精细分析时应采用小波包分析法进行爆破振动信号的分析。该爆破振动信号分析对有效地控制振动速度,降低爆破对周边建筑物的损害和爆破网路设计有着很好的指导意义。

Vibration signal analysis of tunnel periphery hole blasting

In order to find out the influence of periphery hole blasting on controling blasting vibration velocity,the blasting signal of periphery hole was analysized,which was based on the New Construction of Dalian Yuhua 220 kV transmission line.The section of 2# shaft is closed to commercial building,the blasting vibration velocity was controlled effectively by initiation of cutting hole and periphery hole orderly.The blasting signal was measured at the commercial building which is about 6 m away from blasting section.The vibration velocity,duration,dominant frequency,energy-frequency distribution in the blasting vi-bration signal were analyzed by FFT method,wavelet packet analysis method and acceleration power spectrum density method. The results indicated that the maximum single direction velocity of the measure point was 1.1224 cm/s,where is 6 m horizon-tal distance from blasting section in periphery hole blast.The frequency was high,higher than 80 Hz,and the velocity was sat-isfied with the standard of "Safety Regulations for Blasting".At the same time,the similarities and differences of the three methods were analyzed.The FFT spectrum of velocity and energy spectrum of blasting vibration signal calculated by wavelet packet analysis were similar,and it had little difference in calculation of dominant frequency with wavellet packet analysis and very closed to that of acceleration power spectral density.The FFT method can be used to calculated the dominant frequency and evaluated the proportion of energy distribution of vibration signal roughly and rapidly.The wavelet packet analysis method had a high accuracy in calculating dominant frequency,and wavelet packet analysis method was a best choice to precess signal in the case of high precision.The blasting vibration signal analysis has a good guiding significance for the blasting network design, which can effectively control the vibration speed and reduce the damage to the surrounding buildings by blasting.