50t科学爆破振动的衰减特征及地形效应
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摘要
对药量达50t的科学爆破开展了流动强震观测,包括爆破振动的衰减观测和地形效应观测。在分析此次爆破强震记录的基础上,利用萨道夫斯基公式分析了垂直向峰值速度和加速度的衰减规律,爆破地区为中等强度的层状岩石且当地地形沟壑纵横是此次振动能量衰减较快的原因。通过离散小波变换分析(db8小波基函数)得到了此次爆破振动能量的时频分布规律,随着爆心距的增大,爆破振动能量集中的频率减小而振动的持续时间则相对增加。根据中国地震烈度表,在近爆心区振动烈度可以达到Ⅶ度,然而相对于天然地震的烈度衰减,爆破振动烈度的衰减较快。通过比较一个高14m山包的不同位置的强震记录,分析了此次爆破振动的地形效应。由于山包的聚焦效应,山顶的加速度峰值是山脚的2.4倍,且地形效应对某频率段内的振动有选择的放大,该频率段与山包的大小和高度有关。振动轨迹图显示,随着高度的增加,山体的侧向摆动和转动逐渐增强。
Vibration attenuation and topographic effect were monitored near the explosion place of 50 t explosive. Based on the recorded vibration signals,the attenuations of vertical velocity and acceleration were analyzed with the Sadauskas formula. The rapid attenuation of vibration was related with the layered moderate-hardness rocks and the local terrain and gully. The time-frequency distribution of the vibration was obtained by the discrete wavelet transform (db8 wavelet). The frequency of vibration energy concentration was reduced and the duration of the vibration was prolonged with the increase of the distance from the explosion center. According to the Chinese Seismic Intensity Scale,the vibration intensity close to the explosion center is up to Ⅶ,however,the blasting vibration intensity decay faster than the attenuation of earthquake intensity. The topographic effect was discussed by comparing the vibration records at different locations of a 14-m-high hill. Due to the focusing vibration energy of the hill,the peak acceleration on the top of the hill is 2.4 times larger than that at the foot of the hill,and the special frequency bands with the enlarged amplitude is related with the size and the height of the hill. The figure of particle motions indicates that the lateral swing and rotational motion gradually increase from the foot to the top of the hill.
Vibration attenuation and topographic effect were monitored near the explosion place of 50 t explosive. Based on the recorded vibration signals,the attenuations of vertical velocity and acceleration were analyzed with the Sadauskas formula. The rapid attenuation of vibration was related with the layered moderate-hardness rocks and the local terrain and gully. The time-frequency distribution of the vibration was obtained by the discrete wavelet transform (db8 wavelet). The frequency of vibration energy concentration was reduced and the duration of the vibration was prolonged with the increase of the distance from the explosion center. According to the Chinese Seismic Intensity Scale,the vibration intensity close to the explosion center is up to Ⅶ,however,the blasting vibration intensity decay faster than the attenuation of earthquake intensity. The topographic effect was discussed by comparing the vibration records at different locations of a 14-m-high hill. Due to the focusing vibration energy of the hill,the peak acceleration on the top of the hill is 2.4 times larger than that at the foot of the hill,and the special frequency bands with the enlarged amplitude is related with the size and the height of the hill. The figure of particle motions indicates that the lateral swing and rotational motion gradually increase from the foot to the top of the hill.
引文
[1]吴德伦,叶晓明.工程爆破安全振动速度综合研究[J].岩石力学与工程学报,1997,16(3):266-273.WU De-lun,YE Xiao-ming.Acomprehensive reviewand commendation of blast vibration safety velocity[J].Chi-nese Journal of Rock Mechanics and Engineering,1997,16(3):266-273.
[2]阳生权,廖先葵,刘宝琛.爆破地震安全判据的缺陷与改进[J].爆炸与冲击,2001,21(3):223-228.YANG Sheng-quan,LIAO Xian-kui,LI UBao-chen.Default of thejudging standard of blasting vibration safety ab-stract[J].Explosion and Shock Waves,2001,21(3):223-228.
[3]于海英,于双久.工程爆破场地地震动强度预测研究[J].地震工程与工程振动,2004,24(1):122-129.YU Hai-ying,YU Shuang-jiu.Study on forecasting intensity of ground motion induced by engineering explosion[J].Earthquake Engineering and Engineering Vibration,2004,24(1):122-129.
[4]GB6722-2003,爆破安全规程[S].北京:中国标准出版社,2003:45-46.
[5]黄永祥,黄浩雄,李雄,等.建筑物下爆破地震效应的研究[J].地震研究,2002,25(3):82-89.HUANG Yong-xiang,HUANG Hao-xiong,LI Xiong,et al.Study on explosion vibration effect under buildings[J].Journal of Seismological Research,2002,25(3):82-89.
[6]黄文华,徐全军,沈蔚,等.小波变换在判断爆破地震危害中的应用[J].工程爆破,2001,7(1):24-27.HUANG Wen-hua,XU Quan-jun,SHEN Wei,et al.Application of wavelet transformin evaluation of blasting vi-bration damage[J].Engineering Blasting,2001,7(1):24-27.
[7]中国生,徐国元,熊正明.基于小波变换的爆破地震信号能量分析法的应用研究[J].爆炸与冲击,2006,26(3):222-227.ZHONH Guo-sheng,XU Guo-yuan,XIONG Zheng-ming.Application research of the energy analysis method for blasting seismic signals based on wavelet transform[J].Explosion and Shock Waves,2006,26(3):222-227.
[8]GB/T17742-1999,中国地震烈度表[S].北京:中国标准出版社,1999:1-2.
[9]王海云,谢礼立.近断层地震动模拟现状[J].地球科学进展,2008,23(10):1043-1049.WANG Hai-yun,XIE Li-li.A review on near fault ground motion si mulation[J].Advances in Earth Science,2008,23(10):1043-1049.
[10]Spudich P,Hell weg M,Lee W H K.Directional topographic site response at Tarzana observed in aftershocks of the1994Northridge,California,earthquake:I mplications for mainshock motions[J].Bulletin of the Seismological Society of America,1996,86:S193-S208.
[2]阳生权,廖先葵,刘宝琛.爆破地震安全判据的缺陷与改进[J].爆炸与冲击,2001,21(3):223-228.YANG Sheng-quan,LIAO Xian-kui,LI UBao-chen.Default of thejudging standard of blasting vibration safety ab-stract[J].Explosion and Shock Waves,2001,21(3):223-228.
[3]于海英,于双久.工程爆破场地地震动强度预测研究[J].地震工程与工程振动,2004,24(1):122-129.YU Hai-ying,YU Shuang-jiu.Study on forecasting intensity of ground motion induced by engineering explosion[J].Earthquake Engineering and Engineering Vibration,2004,24(1):122-129.
[4]GB6722-2003,爆破安全规程[S].北京:中国标准出版社,2003:45-46.
[5]黄永祥,黄浩雄,李雄,等.建筑物下爆破地震效应的研究[J].地震研究,2002,25(3):82-89.HUANG Yong-xiang,HUANG Hao-xiong,LI Xiong,et al.Study on explosion vibration effect under buildings[J].Journal of Seismological Research,2002,25(3):82-89.
[6]黄文华,徐全军,沈蔚,等.小波变换在判断爆破地震危害中的应用[J].工程爆破,2001,7(1):24-27.HUANG Wen-hua,XU Quan-jun,SHEN Wei,et al.Application of wavelet transformin evaluation of blasting vi-bration damage[J].Engineering Blasting,2001,7(1):24-27.
[7]中国生,徐国元,熊正明.基于小波变换的爆破地震信号能量分析法的应用研究[J].爆炸与冲击,2006,26(3):222-227.ZHONH Guo-sheng,XU Guo-yuan,XIONG Zheng-ming.Application research of the energy analysis method for blasting seismic signals based on wavelet transform[J].Explosion and Shock Waves,2006,26(3):222-227.
[8]GB/T17742-1999,中国地震烈度表[S].北京:中国标准出版社,1999:1-2.
[9]王海云,谢礼立.近断层地震动模拟现状[J].地球科学进展,2008,23(10):1043-1049.WANG Hai-yun,XIE Li-li.A review on near fault ground motion si mulation[J].Advances in Earth Science,2008,23(10):1043-1049.
[10]Spudich P,Hell weg M,Lee W H K.Directional topographic site response at Tarzana observed in aftershocks of the1994Northridge,California,earthquake:I mplications for mainshock motions[J].Bulletin of the Seismological Society of America,1996,86:S193-S208.
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