摘要
耦合介质对炸药震源激发的爆炸地震波的能量与频率特征有较大影响。为提高地震勘探中炸药震源激发地震波的品质,选取了空气、水、细沙和岩土4种介质作为耦合介质,进行了土中爆炸试验来对比分析耦合介质对地震波特征的影响规律。利用快速傅里叶变换(FFT)将频率分为不同的频率带,对距炸药震源5~65 m内收集到的地面震动信号进行分析。试验结果表明:以水为耦合介质的炸药震源产生的地震波能量相对要高,尤其在25~100 Hz内,能量对比差别更加明显;以空气为耦合介质的炸药震源次之;以水为耦合介质炸药震源主频最高,随传播距离衰减速度较慢;岩土全耦合炸药震源在25 m范围内主频较高,但衰减速度最快,随着传播距离下降较快。综上,以水为耦合介质与其他相介质对比可产生较高能量和主频,更加符合地震勘探要求。
Coupling media around the explosive source have significant effect on the characteristics of the energy and basic frequency of the seismic wave. In order to improve the quality of seismic wave generated by explosive source in seismic exploration,the influences of the properties of coupling media on the features of seismic wave are studied,in which four kinds of media,such as air,water,fine sand and coarse soil,are used as the coupling media in the field test. The effects of coupling media on the quality of seismic are analyzed by comparing the amplitudes and frequencies of the waves recorded in the explosion test in soil. The frequencies are divided into different frequency bandsthrough the fast Fourier transform( FFT),and the ground vibrations recorded in the range from 5 m to 65 m away from the explosive source are analyzed. It could be found from the experimental results that the seismic wave energy in water as a coupling medium is the highest,especially at the effective frequency band of 25 Hz to 100 Hz; the energy of the wave generated in air comes second. For frequency domain,the highest basic frequency is appeared in water; meanwhile the attenuation of the basic frequency is the slowest. In the coarse soil,the basic frequency is higher in the near field in the range of 25 m. But the basic frequency is reduced withthe increase in the distance beyond the range. The experimental study shows that the water could be the better coupling medium,which can be used in exciting the seismic wave by the explosive source to meet the requirement in seismic exploration.
出处
《兵工学报》
EI
CAS
CSCD
北大核心
2014年第S2期115-121,共7页
Acta Armamentarii
基金
国家重大专题项目(2011ZX05006-002)
关键词
爆炸力学
耦合介质
频率带能量
地震波品质
土中爆炸
地震波
explosion mechanics
coupling medium
seismic wave energy
quality of seismic wave
explosion in soil
seismic wave
