地脉动在福州市区地基土层场地评价中的应用
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摘要
根据实际观测资料研究了福州市区的地脉动特征以及地脉动频谱特性与场地有关参数之间的关系。结果表明,地脉动的频谱特性能够反映覆盖层厚度和地基土刚度的变化;可以通过研究场地地脉动的特性来评价研究区岩土的动力特性;可以通过建立场地土覆盖层厚度、剪切波速与地脉动卓越周期之间的相关关系,揭示它们的内在规律。
The dynamical characteristics of ground soil and structure of frequency spectrum of ground microtremor in Fuzhou, Fujian province, are studied in this paper. The ground microtremor signals were observed, and the signals were analyzed by fast Fourier transform method(FFT). The characteristics of structure of frequency spectrum and response of ground soil to frequency of ground microtremor are revealed, and the function of microtremor with frequency-dependence and frequency-selection for different foundation soil strata is also researched. The results are shown as follows. First, ground microtremor is a kind of geophysics information with abundant intension. The frequency characteristics of ground microtremor can be obtained by spectral analyses of its signals, which can be used to probe into dynamical characteristics of rock and soil of studied area. Secondly, there exists a function with frequency-dependence and frequency-selection for the response of site soil. The change of predominant period of ground microtremor is closely related to the formation of site soil layers, and mutually corresponds to the change of engineering geological conditions of the site. Therefore, the structure and feature of different foundation soil strata can be distinguished with different kinds of frequency response of site. Thirdly, the structure of rock and soil layers directly influences the spectral structure characteristics of ground microtremor. The covered layer with the structure of different foundation soil strata is related to the frequency of ground microtremor. The thickness of covered layer is one of important factors to affect the predominant period of ground microtremor. Fourthly, there exist some corresponding relationships between spectral structure characters of ground microtremor and shear wave velocity of site soil layers. The outcomes of these two kinds of tests can be conferred each other. Fifthly, the correlations among predominant period of ground microtremor, thickness, and value of shear wave velocity of covered layer are established. The study results have been applied to selecting the infrastructure and buried depth of high building foundation in the coastal area of Fujian province.
The dynamical characteristics of ground soil and structure of frequency spectrum of ground microtremor in Fuzhou, Fujian province, are studied in this paper. The ground microtremor signals were observed, and the signals were analyzed by fast Fourier transform method(FFT). The characteristics of structure of frequency spectrum and response of ground soil to frequency of ground microtremor are revealed, and the function of microtremor with frequency-dependence and frequency-selection for different foundation soil strata is also researched. The results are shown as follows. First, ground microtremor is a kind of geophysics information with abundant intension. The frequency characteristics of ground microtremor can be obtained by spectral analyses of its signals, which can be used to probe into dynamical characteristics of rock and soil of studied area. Secondly, there exists a function with frequency-dependence and frequency-selection for the response of site soil. The change of predominant period of ground microtremor is closely related to the formation of site soil layers, and mutually corresponds to the change of engineering geological conditions of the site. Therefore, the structure and feature of different foundation soil strata can be distinguished with different kinds of frequency response of site. Thirdly, the structure of rock and soil layers directly influences the spectral structure characteristics of ground microtremor. The covered layer with the structure of different foundation soil strata is related to the frequency of ground microtremor. The thickness of covered layer is one of important factors to affect the predominant period of ground microtremor. Fourthly, there exist some corresponding relationships between spectral structure characters of ground microtremor and shear wave velocity of site soil layers. The outcomes of these two kinds of tests can be conferred each other. Fifthly, the correlations among predominant period of ground microtremor, thickness, and value of shear wave velocity of covered layer are established. The study results have been applied to selecting the infrastructure and buried depth of high building foundation in the coastal area of Fujian province.
引文
1 刘惠珊,张在明.地震区的场地与地基基础[M].北京:中国建筑工业出版社,1994
2 章在墉,李文艺,陶能付.长周期地面脉动在地震小区划中的应用[J].同济大学学报,1994,22(4) :421～426
3 吴世明.土介质中的波[M].北京:科学出版社,1997,383～399
4 简文彬,李哲生,黄真萍等.地基土层构造与地微动频率效应[A].见:刘汉龙.土动力学与岩土地震工程[C].北京:中国建筑工业出版社,2002,416～421
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9 高广运,吴世明,周健等.场地卓越周期的讨论与溯定[J].工程勘察,2000． (5) :29～31
10 丁志俊.城市地震小区划及工程地震勘探[M].北京:地震出版社,1991
11 Castro R R, Mucciarelli M, Pacor F. S-waves site-response estimates using horizontal-to-vertical spectral ratios[J]. Bull. Seism. Soc. Am., 1997, 87(1) : 256～260
12 Mura Naka. A method for dynamic character estimation of subsurface using microtremor on the ground surface[J]. Q. R. of RTR1, 1999, 30(1) : 25～33
13 Coueel F, Mora P. Simulation-besed comparison of four site-response estimation technique[J]. Bull. Seism. Soc. Am., 1998, 88(1) : 30～42
14 高大钊.地基基础测试新技术[M].北京:机械工业出版社,1999
15 王兴泰.工程与环境物探新方法新技术[M].北京:地质出版社,2001
16 Masanori Horike. Inversion of phase velocity of long-period microtremors of the S-wave velocity structure down the basement in urbanized areas[J]. Journal of Physics of the Earth, 1985, 33(2) : 59～61
17 Seekins L C, Wennerherg L, Mwrgheriti L, et al. Site amplification at five locations in San Francisco, California: a comparison of waves, codas and microtremors[J]. Bull. Seism. Soc. Am., 1996, 86(2) : 320～328
18 Katsuaki Konno, Ohmachi Tatsuo. Ground-motion characteristics estimated from spectral ratio between horizontal and vertical components of microtremor[J]. Bull. Seism. Soc. Am., 1998, 88(1) : 228～241
19 建设部综合勘察研究院.场地微振动测量技术规程(CECS 74:95) [S].北京:中国计划出版社,1996
20 庄楚强,吴亚森.应用数理统计基础[M].广州:华南理工大学出版社,1999
2 章在墉,李文艺,陶能付.长周期地面脉动在地震小区划中的应用[J].同济大学学报,1994,22(4) :421～426
3 吴世明.土介质中的波[M].北京:科学出版社,1997,383～399
4 简文彬,李哲生,黄真萍等.地基土层构造与地微动频率效应[A].见:刘汉龙.土动力学与岩土地震工程[C].北京:中国建筑工业出版社,2002,416～421
5 王锺琦,张荣祥,汪敏等.地震区工程选址手册[M].北京:中国建筑工业出版社,1994
6 胡钧,杜坚.上海场地土的脉动特性及剪切波速特征[J].物探与化探,1997,21(4) :305～307
7 林建生,王源毅.泉州市地面脉动特征[J].西北地震学报,1993,15(3) :76～80
8 简文彬,李哲生,黄真萍等.福建沿海地区地微动的谱结构特征[J].工程地质学报,2002,10(2) :216～219
9 高广运,吴世明,周健等.场地卓越周期的讨论与溯定[J].工程勘察,2000． (5) :29～31
10 丁志俊.城市地震小区划及工程地震勘探[M].北京:地震出版社,1991
11 Castro R R, Mucciarelli M, Pacor F. S-waves site-response estimates using horizontal-to-vertical spectral ratios[J]. Bull. Seism. Soc. Am., 1997, 87(1) : 256～260
12 Mura Naka. A method for dynamic character estimation of subsurface using microtremor on the ground surface[J]. Q. R. of RTR1, 1999, 30(1) : 25～33
13 Coueel F, Mora P. Simulation-besed comparison of four site-response estimation technique[J]. Bull. Seism. Soc. Am., 1998, 88(1) : 30～42
14 高大钊.地基基础测试新技术[M].北京:机械工业出版社,1999
15 王兴泰.工程与环境物探新方法新技术[M].北京:地质出版社,2001
16 Masanori Horike. Inversion of phase velocity of long-period microtremors of the S-wave velocity structure down the basement in urbanized areas[J]. Journal of Physics of the Earth, 1985, 33(2) : 59～61
17 Seekins L C, Wennerherg L, Mwrgheriti L, et al. Site amplification at five locations in San Francisco, California: a comparison of waves, codas and microtremors[J]. Bull. Seism. Soc. Am., 1996, 86(2) : 320～328
18 Katsuaki Konno, Ohmachi Tatsuo. Ground-motion characteristics estimated from spectral ratio between horizontal and vertical components of microtremor[J]. Bull. Seism. Soc. Am., 1998, 88(1) : 228～241
19 建设部综合勘察研究院.场地微振动测量技术规程(CECS 74:95) [S].北京:中国计划出版社,1996
20 庄楚强,吴亚森.应用数理统计基础[M].广州:华南理工大学出版社,1999
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