爆破震动信号的多分辨小波分析
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摘要
采用小波分析和快速傅立叶变换相结合的方法,对工程案例的爆破震动近、中远区的实测原始信号进行小小波分解和重构,得到重构后各子频带的时间信号及频谱,在此基础上通过Matlab语言编写程序研究爆破地震波沿各分区信号的频谱及能量分布特征。指出:爆破震动各分区的主频从大到小排序为:近区>中区>远区;随着比例距离的增加,低频带能量所占信号总能量的比例升高,高频带能量所占比例下降;频率越低的频带信号,持续时间越长;除主频所在频带外,在0～2.441 5 Hz频段(比较接近建筑物的自振频率),爆破震动信号在水平方向占有不小的能量比例,故建筑物进行结构设计时考虑水平方向的抗震尤为重要。
With the methods of wavelet analysis and fast Fourier transform,actual original signals from engineering project in near,medium and far zones of blasting vibration are separately decomposed and reconstructed;and time signals and spectra of all sub-frequencybands are obtained.On this basis,distribution characteristics of spectra and energy of blasting seismic waves along all zones are studied with Matlab;and it is pointed out,that the values of dominant frequency in blasting vibration zones is in attenuation sequence: near zone,medium zone,far zone;as the scaled distance increases,low frequency bands share higher proportion of total signal energy,while high frequency bands share lower;signals in lower frequency bands have longer duration;in addition to the frequency band that the dominant frequency locates in,when the band is from 0 to 2.441 5 Hz(close to the natural frequency of the buildings),blasting vibration signals in the horizontal direction occupy an assignable proportion of the energy;and thus the aseismic construction in horizontal direction is especially important for building structure designs.
With the methods of wavelet analysis and fast Fourier transform,actual original signals from engineering project in near,medium and far zones of blasting vibration are separately decomposed and reconstructed;and time signals and spectra of all sub-frequencybands are obtained.On this basis,distribution characteristics of spectra and energy of blasting seismic waves along all zones are studied with Matlab;and it is pointed out,that the values of dominant frequency in blasting vibration zones is in attenuation sequence: near zone,medium zone,far zone;as the scaled distance increases,low frequency bands share higher proportion of total signal energy,while high frequency bands share lower;signals in lower frequency bands have longer duration;in addition to the frequency band that the dominant frequency locates in,when the band is from 0 to 2.441 5 Hz(close to the natural frequency of the buildings),blasting vibration signals in the horizontal direction occupy an assignable proportion of the energy;and thus the aseismic construction in horizontal direction is especially important for building structure designs.
引文
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[12]刘涛,曾祥利,曾军.实用小波分析入门[M].北京:国防工业出版社,2006:70-78.
[2]胡昌华,张军波.基于MATLAB的系统分析与设计—小波分析[M].西安:西安电子科技大学,2000:265-266.
[3]王宏禹.非平稳随机信号分析与处理[M].北京:国防工业出版社,1999:12-20.
[4]李宏男,王丙乾,林皋.爆破地震效应若干问题的研究[J].爆炸与冲击,1996,16(1):61-67.
[5]李洪涛,舒大强.爆破震动衰减规律的影响因素[J].武汉大学学报,2005,38(1):79-82.
[6]MA G W,HAO H,ZHOU Y X.Assessment of structure damage to blasting induced[J].Engineering Structures,2000,(22):1378-1389.
[7]何军,于亚伦,梁文基.爆破震动信号的小波分析[J].岩土工程学报,1998,20(1):47-50.
[8]林大超,施惠基,白春华,等.爆炸地震效应的时频分析[J].爆炸与冲击,2003,23(1):31-36.
[9]凌同华,李夕兵.基于小波变换的时-能分布确定微差爆破的实际延迟时间[J].岩石力学与工程学报,2004,23(13):2266-2270.
[10]凌同华,李夕兵.地下工程爆破震动信号能量分布特征的小波包分析[J].爆炸与冲击,2004,24(1):63-68.
[11]黄文华,徐全军,沈蔚,等.小波变换在判断爆炸地震危害中的应用[J].工程爆破,2001,7(1):24-27.
[12]刘涛,曾祥利,曾军.实用小波分析入门[M].北京:国防工业出版社,2006:70-78.
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