基于HHT频谱分析研究断层对爆破地震波传播的影响

Analysis on the influence of fault on the propagation of blasting seismic wave based on HHT spectrum analysis

为了研究断层对爆破地震波传播规律的影响,选用位于385中段450水平断层FⅢ-0附近的24线和26线布置测点。利用Matlab软件对测振仪测得的爆破振动信号分析。使用经验模态EMD先分解出高频段再过渡到低频段,直到最后一个分量。运用HHT将分量变换得到HHT三维谱、能量分布图、边际谱及瞬时能量图。通过对穿过断层前后的爆破振动信号进行对比分析得到,爆破地震波在穿过断层后能量幅值降低,但是低频部分能量增加;边际谱频带变宽、能量分散、低频作用更加明显;瞬时能量谱峰值减小10倍左右,振动持续时间增加,表明低频作用更强。

In order to study the influence of faults on the propagation law of blasting seismic wave,the 24 and 26 lines near the 450 horizontal fault FⅢ-0 in the middle section of 385 were selected to lay out the measuring points.The blasting vibration signal measured by the vibrometer was analyzed by Matlab software.The empirical mode EMD was used to decompose the high frequency band and then transition to the low frequency band until the last component.The HHT three-dimensional spectrum,energy distribution diagram,marginal spectrum and instantaneous energy diagram were obtained by HHT component transformation.Through the comparative analysis of blasting vibration signals before and after passing through the fault,the energy amplitude of blasting seismic wave decreased after passing through the fault,but the energy of low-frequency part increased.Marginal spectrum frequency band became wider,energy dispersed,low frequency effect was more obvious;The peak value of instantaneous energy spectrum decreased by about 10 times,and the duration of vibration increased,indicating that the low frequency effect is stronger.