瑞雷波地基检测中震源及“之”字形频散曲线的数值研究
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摘要
瞬态瑞雷波技术与传统方法相比具有测试技术简单易行、无需钻孔、浅层分辨率高以及高效经济等优点,已经被广泛地应用于地基检测中,但由于缺少大量理论指导,特别是数值模拟方面的研究,其应用受到限制。本文利用有限元软件LS-DYNA对瑞雷波地基检测过程进行了数值模拟,研究了地基检测中震源和瑞雷波“之”字形频散曲线问题,得出以下结论:
(1)通过对半空间单层土体数值模拟提取频散曲线的误差的研究分析,说明用有限元方法模拟瑞雷波地基检测过程是可行的。在此基础上,通过对不同震源参数情况下得到频散曲线误差分析发现,加载面越大,频散曲线误差越大;荷载作用时间过大或过小,频散曲线出现弯曲和不规则;荷载大小对频散曲线形态几乎没有影响。这就要求在实际工程中应选择较小的加载面,荷载作用时间适中的震源。
(2)通过对四种典型地层(递增型地层、含软弱下伏层地层、含软弱夹层地层、含硬夹层地层)的27个模型瑞雷波“之”字形频散曲线特征的研究发现:对于递增型地层,频散曲线不会出现“之”字形,而且很难通过拐点判断分层位置;而对于其它三种非递增型地层,频散曲线则会出现两种类型的“之”字形,其中含软弱夹层地层,“之”字形的位置和尺寸与软夹层的位置和层厚有较好的对应关系。本文还将数值模拟计算结果与实测结果以及解析解进行了比较,进一步验证了数值方法研究瑞雷波地基检测过程的可行性及“之”字形频散曲线的形成原因。
(3)当含软夹层地层有空洞时,频散曲线“之”字形变大,而且频散曲线与无空洞时相比,高频部分出现缺失。而且当空洞位于软夹层,震源下以及近道检波器附近时,对“之”字形频散曲线的形态影响最大。
本文的研究为工程实际中震源参数的选取提供可靠依据,也为在实际工程中利用瑞雷波频散曲线的形状判定地层类型和软弱夹层位置提供了重要参考,而在空洞探测方面也提供一定依据。
Transient Rayleigh technology has the following advantages over traditional method: easy and feasible testing technique, no need to drill, high resolution in shallow stratums and high efficiency and low cost. It is widely used in stratum exploration, but its application is limited because of no many theory guides; especially numerical simulation research. This article uses the finite elements software LS-DYNA to simulate the processing of Rayleigh wave stratum exploration, and study source and Rayleigh wave zigzag dispersion curve. Then we obtain the following conclusions:
(1)Through analysis about errors of extracting dispersion curve simulate from half space single stratum, we know it is feasible to use the finite element method to simulate the processing of Rayleigh wave stratum exploration. On that basis, through analisis about errors of extracting dispersion curve in the case of different source parameters, we discover: average errors of dispersion curve become lager with augment of loading area; dispersion curves appear bend and abnormity, when loading time is too long or too short; but load values hardly act any effect on the shape of dispersion curves. So we should use sorurce with small loading area and moderate loading time in actual engineering.
(2)Through study about Rayleigh wave zigzag dispersion curve of 27 models of four typical stratums (stratum of Rayleigh wave velocity would increase with wavelength, the under-layer is soft, weak interlayer, hard interlayer), We know that dispersion curves of the stratum of Rayleigh wave velocity would increase with wavelength can’t appear zigzag, but we can not juge layered position through inflections. However, Rayleigh wave dispersion curves of other stratums will appear two different types zigzag. For the sratums containing weak interlayer, zigzag position and size of stratums matches better with position and layer thickness of weak interlayer. This article also compares numerical simulation results with analytical solution, and further verifies feasibility of reasearching the processing of Rayleigh wave stratum exploration; also explains the genesis of zigzag dispersion curve.
(3)When stratums containing weak interlayer have a hole, zigzag dispersion curve becomes larger. And comparing with stratums containing no hole, high frequency of dispersion curve appears missing points. When holes locate in weak interlayer, under source and close to nearby geophones, the shape of zigzag dispersion curve varies largest.
The results of the article offer reliable basis for the choice of source parameters in actual engineering, supply important reference for using dispersion curve shape to determine stratum types and position of weak interlayer in actual engineering, and also provide certain foundation for hole exploration.
(1)通过对半空间单层土体数值模拟提取频散曲线的误差的研究分析,说明用有限元方法模拟瑞雷波地基检测过程是可行的。在此基础上,通过对不同震源参数情况下得到频散曲线误差分析发现,加载面越大,频散曲线误差越大;荷载作用时间过大或过小,频散曲线出现弯曲和不规则;荷载大小对频散曲线形态几乎没有影响。这就要求在实际工程中应选择较小的加载面,荷载作用时间适中的震源。
(2)通过对四种典型地层(递增型地层、含软弱下伏层地层、含软弱夹层地层、含硬夹层地层)的27个模型瑞雷波“之”字形频散曲线特征的研究发现:对于递增型地层,频散曲线不会出现“之”字形,而且很难通过拐点判断分层位置;而对于其它三种非递增型地层,频散曲线则会出现两种类型的“之”字形,其中含软弱夹层地层,“之”字形的位置和尺寸与软夹层的位置和层厚有较好的对应关系。本文还将数值模拟计算结果与实测结果以及解析解进行了比较,进一步验证了数值方法研究瑞雷波地基检测过程的可行性及“之”字形频散曲线的形成原因。
(3)当含软夹层地层有空洞时,频散曲线“之”字形变大,而且频散曲线与无空洞时相比,高频部分出现缺失。而且当空洞位于软夹层,震源下以及近道检波器附近时,对“之”字形频散曲线的形态影响最大。
本文的研究为工程实际中震源参数的选取提供可靠依据,也为在实际工程中利用瑞雷波频散曲线的形状判定地层类型和软弱夹层位置提供了重要参考,而在空洞探测方面也提供一定依据。
Transient Rayleigh technology has the following advantages over traditional method: easy and feasible testing technique, no need to drill, high resolution in shallow stratums and high efficiency and low cost. It is widely used in stratum exploration, but its application is limited because of no many theory guides; especially numerical simulation research. This article uses the finite elements software LS-DYNA to simulate the processing of Rayleigh wave stratum exploration, and study source and Rayleigh wave zigzag dispersion curve. Then we obtain the following conclusions:
(1)Through analysis about errors of extracting dispersion curve simulate from half space single stratum, we know it is feasible to use the finite element method to simulate the processing of Rayleigh wave stratum exploration. On that basis, through analisis about errors of extracting dispersion curve in the case of different source parameters, we discover: average errors of dispersion curve become lager with augment of loading area; dispersion curves appear bend and abnormity, when loading time is too long or too short; but load values hardly act any effect on the shape of dispersion curves. So we should use sorurce with small loading area and moderate loading time in actual engineering.
(2)Through study about Rayleigh wave zigzag dispersion curve of 27 models of four typical stratums (stratum of Rayleigh wave velocity would increase with wavelength, the under-layer is soft, weak interlayer, hard interlayer), We know that dispersion curves of the stratum of Rayleigh wave velocity would increase with wavelength can’t appear zigzag, but we can not juge layered position through inflections. However, Rayleigh wave dispersion curves of other stratums will appear two different types zigzag. For the sratums containing weak interlayer, zigzag position and size of stratums matches better with position and layer thickness of weak interlayer. This article also compares numerical simulation results with analytical solution, and further verifies feasibility of reasearching the processing of Rayleigh wave stratum exploration; also explains the genesis of zigzag dispersion curve.
(3)When stratums containing weak interlayer have a hole, zigzag dispersion curve becomes larger. And comparing with stratums containing no hole, high frequency of dispersion curve appears missing points. When holes locate in weak interlayer, under source and close to nearby geophones, the shape of zigzag dispersion curve varies largest.
The results of the article offer reliable basis for the choice of source parameters in actual engineering, supply important reference for using dispersion curve shape to determine stratum types and position of weak interlayer in actual engineering, and also provide certain foundation for hole exploration.
引文
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3严寿民.瞬态瑞雷波勘探方法[J].物探与化探. 1992,16(2):113~119
4 Haskell N.A.. The dispersion of surface waves on multilayered media[J]. Bull Seism Soc Am. 1953,43:17~34
5 Rosebaum J.H.. A note on the computation of Rayleigh wave dispersion curves for layered elastic media[J]. Bull seism soc AM. 1964,53(3):1013~1019
6 Bixing Zhang, M. Yu, C.Q., Lan, Wei Xiong. Elastic Wave and excitation mechanism of surface waves in multilayered media[J]. J. Acoust. Soc. Am.. 1996,100(6):3527~3538
7 Dong-Joo Min, Hyoung-Soo Kim. Feasibility of the surface-wave method for the assessment of physical properties of a dam using numerical analysis[J]. Journal of Applied Geophysics. 2006,59:236~243
8梁志强.层状介质中多模式面波频散曲线研究[D].长安大学硕士学位论文. 2005:1~3
9章哲辉.瑞雷波面波勘探在空洞探测中的应用[J].湖南水利水电. 2003,1:21~22
10单娜琳,程志平.高阶模态面波在软弱薄层探测中的应用[J].桂林工学院学报. 2004,24(2):155~157
11陈灯.岩土工程地下空区瑞雷波探测技术[D].中南大学硕士学位论文. 2005:1~15
12 Jianghai Xia, Richard D. Miller, Choon B. Park, Gang Tian. Inversion of high frequency surface waves with fundamental and higher modes[J]. Journal of Applied Geophysics. 2003,52(1):45~57
13 Jianghai Xia, Yixian Xu, Chao Chen, Ronald D. Kaufmann, Yinhe Luo. Simple equations guide high-frequency surface-wave investigationtechniques[J]. Soil Dynamics and Earthquake Engineering. 2006,26:395~403
14 Xianhai Song, Hanming Gu, Jiangping Liu, Xueqiang Zhang. Estimation of shallow subsurface shear-wave velocity by inverting fundamental and higher-mode Rayleigh waves[J]. Soil Dynamics and Earthquake Engineering. 2007,27:599~607
15 Xia, J., Miller, R.D., Park, C.B.. Estimation of near-surface shear-wave velocity by inversion of Rayleigh wave[J]. Geophysics. 1999,64 (3):691~700
16凡友华.考虑多阶模的Rayleigh波勘探应用研究[D].北京大学博士后研究工作报告. 2003:25~27
17鲁来玉,张碧星,汪承灏.基于瑞利波高阶模式反演的实验研究[J].地球物理学报. 2006,49(4):1082-1089
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19张碧星,鲁来玉,鲍光淑.瑞利波勘探中“之”字形频散曲线研究[J].地球物理学报. 2003,45(2):263~273
20陈祥,孙进忠,刘景儒.瑞雷波“之”形速度-深度曲线的成因[J].地球物理学进展. 2004,19(4):860~863
21张金清,梁青,陈超.软弱夹层瑞雷波频散曲线特征[J].工程地球物理学报. 2005,208~215
22夏唐代,吴世明.流体-固体介质中瑞利波特性[J].水利学报. 1994,1:69~79
23赖思静,贾学明,杨建国.软弱地层中瑞雷波传播的数值模拟研究[J].公路交通技术. 2005,5:57~62
24 Young S. Cho, Feng-Bao Lin. Spectral analysis of surface waves in single and multi-layer slabs with finite thickness using finite element modeling[J]. NDT&E International. 2005,38:195~202
25杨生.复杂地层条件下瑞利波传播特性的数值分析研究[D].西安理工大学硕士学位论文. 2006:15~16
26 A. Nasseri-Moghaddam, G. Cascante, C. Phillips, D.J. Hutchinso. Effects of underground cavities on Rayleigh waves-Field and numerical experiments[J]. Soil Dynamics and Earthquake Engineering. 2007,27:300~313
27周竹生,刘喜亮,熊孝雨.弹性介质中瑞雷面波有限差分法正演模拟[J].地球物理学报. 2007,50(2):567~573
28单娜琳,程志平,刘云祯.工程地震勘探[M].冶金工业出版社. 2006:122~131
29崔瑞华,谷社峰,杨德全,李清华.瑞雷面波在地基勘查中的应用[J].地质找矿论从. 2005,20(增):170~173
30 Daniel Royer, Dominique Clorennec. An improved approximation for the Rayleigh wave equation[J]. Ultrasonics. 2007,46: 23~24
31贾辉.瞬态瑞利波法在隐伏断层探测中的应用研究[J].中国地震局地球物理研究所硕士学位论文. 2007:22~36
32 A. Zerwer, G. Cascante, J. Hutchinson. Parameter Estimation in Finite Element Simulations of Rayleigh Waves[J]. Geotechnical and Geoenvironmental Engineering. 2002,3:250~261
33陈龙珠,严细水,赵永倩.关于面波法检测地基波速中的测点布置问题[J].岩土工程学报. 2003,25(1):63~66
34 Yixian Xu, Jianghai Xia, Richard D. Miller. Quantitative estimation of minimum offset for multichannel surface-wave survey with actively exciting source[J]. Journal of Applied Geophysics. 2006,59:117~125
35 Longzhu Chen, Jinying Zhu, Xishui Yan, Chunyu Song. On arrangement of source and receivers in SASW testing[J]. Soil Dynamics and Earthquake Engineering. 2004,24:389~396
36凡友华,陈晓非,刘雪峰,刘家琦,陈小宏. Rayleigh波的频散方程高频近似分解和多模式激发数目[J].地球物理学报. 2007,50(1):233~239
37贾学明,杨建国,赖思静.路基边界对瑞利波检测影响的数值研究[J].岩土力学[J]. 2004,25(增):256~260
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41杨天春,何继善,吕绍林,王齐仁,姚成华.三层层状介质中瑞利波的频散曲线特征[J].物探与物化. 2004,28(1):41~45
42单娜琳,程志平.高阶模态面波在软弱薄层探测中的应用[J].桂林工学院学报. 2004,24(2):155~157
43凡友华.层状介质中瑞利面波频散曲线的正反演研究[D].哈尔滨工业大学博士学位论文. 2001:11~22
44 Schwab, F.. Surface-wave Dispersion Computation: Knopoff’s Method[J]. Bull. Seism. Soc. Am.. 1970,60:1491~1520
45牛建军,苏亚志,郑作栋.瑞雷波勘探在地下洞穴探测中的应用[J].世界地质. 1997,16(2):79~82
46朱翔鹏,张学强,严哲.瑞雷波在探测地下防空洞的应用研究[J].工程地球物理学报. 2007,4(1):58~61
47 N. Gucunski, V. Ganji, M.H. Maher. Effects of obstacles on Rayleigh wave dispersion obtained from the SASW test[J]. Soil Dynamics and Earthquake Engineering. 1996,15:223~231
48 A. Nasseri-Moghaddam, G. Cascante, C. Phillips, D.J. Hutchinso. Effects of underground cavities on Rayleigh waves-Field and numerical experiments[J]. Soil Dynamics and Earthquake Engineering. 2007,27:300~313
2王书增,谭春,陈刚.面波法在堤坝隐患勘查中的应用[J].地球物理学进展. 2005,20(1):262~266
3严寿民.瞬态瑞雷波勘探方法[J].物探与化探. 1992,16(2):113~119
4 Haskell N.A.. The dispersion of surface waves on multilayered media[J]. Bull Seism Soc Am. 1953,43:17~34
5 Rosebaum J.H.. A note on the computation of Rayleigh wave dispersion curves for layered elastic media[J]. Bull seism soc AM. 1964,53(3):1013~1019
6 Bixing Zhang, M. Yu, C.Q., Lan, Wei Xiong. Elastic Wave and excitation mechanism of surface waves in multilayered media[J]. J. Acoust. Soc. Am.. 1996,100(6):3527~3538
7 Dong-Joo Min, Hyoung-Soo Kim. Feasibility of the surface-wave method for the assessment of physical properties of a dam using numerical analysis[J]. Journal of Applied Geophysics. 2006,59:236~243
8梁志强.层状介质中多模式面波频散曲线研究[D].长安大学硕士学位论文. 2005:1~3
9章哲辉.瑞雷波面波勘探在空洞探测中的应用[J].湖南水利水电. 2003,1:21~22
10单娜琳,程志平.高阶模态面波在软弱薄层探测中的应用[J].桂林工学院学报. 2004,24(2):155~157
11陈灯.岩土工程地下空区瑞雷波探测技术[D].中南大学硕士学位论文. 2005:1~15
12 Jianghai Xia, Richard D. Miller, Choon B. Park, Gang Tian. Inversion of high frequency surface waves with fundamental and higher modes[J]. Journal of Applied Geophysics. 2003,52(1):45~57
13 Jianghai Xia, Yixian Xu, Chao Chen, Ronald D. Kaufmann, Yinhe Luo. Simple equations guide high-frequency surface-wave investigationtechniques[J]. Soil Dynamics and Earthquake Engineering. 2006,26:395~403
14 Xianhai Song, Hanming Gu, Jiangping Liu, Xueqiang Zhang. Estimation of shallow subsurface shear-wave velocity by inverting fundamental and higher-mode Rayleigh waves[J]. Soil Dynamics and Earthquake Engineering. 2007,27:599~607
15 Xia, J., Miller, R.D., Park, C.B.. Estimation of near-surface shear-wave velocity by inversion of Rayleigh wave[J]. Geophysics. 1999,64 (3):691~700
16凡友华.考虑多阶模的Rayleigh波勘探应用研究[D].北京大学博士后研究工作报告. 2003:25~27
17鲁来玉,张碧星,汪承灏.基于瑞利波高阶模式反演的实验研究[J].地球物理学报. 2006,49(4):1082-1089
18罗银河,夏江海,刘江平,刘庆生.基阶与高阶瑞利波联合反演研究[J].地球物理学报. 2008,51(1):242~249
19张碧星,鲁来玉,鲍光淑.瑞利波勘探中“之”字形频散曲线研究[J].地球物理学报. 2003,45(2):263~273
20陈祥,孙进忠,刘景儒.瑞雷波“之”形速度-深度曲线的成因[J].地球物理学进展. 2004,19(4):860~863
21张金清,梁青,陈超.软弱夹层瑞雷波频散曲线特征[J].工程地球物理学报. 2005,208~215
22夏唐代,吴世明.流体-固体介质中瑞利波特性[J].水利学报. 1994,1:69~79
23赖思静,贾学明,杨建国.软弱地层中瑞雷波传播的数值模拟研究[J].公路交通技术. 2005,5:57~62
24 Young S. Cho, Feng-Bao Lin. Spectral analysis of surface waves in single and multi-layer slabs with finite thickness using finite element modeling[J]. NDT&E International. 2005,38:195~202
25杨生.复杂地层条件下瑞利波传播特性的数值分析研究[D].西安理工大学硕士学位论文. 2006:15~16
26 A. Nasseri-Moghaddam, G. Cascante, C. Phillips, D.J. Hutchinso. Effects of underground cavities on Rayleigh waves-Field and numerical experiments[J]. Soil Dynamics and Earthquake Engineering. 2007,27:300~313
27周竹生,刘喜亮,熊孝雨.弹性介质中瑞雷面波有限差分法正演模拟[J].地球物理学报. 2007,50(2):567~573
28单娜琳,程志平,刘云祯.工程地震勘探[M].冶金工业出版社. 2006:122~131
29崔瑞华,谷社峰,杨德全,李清华.瑞雷面波在地基勘查中的应用[J].地质找矿论从. 2005,20(增):170~173
30 Daniel Royer, Dominique Clorennec. An improved approximation for the Rayleigh wave equation[J]. Ultrasonics. 2007,46: 23~24
31贾辉.瞬态瑞利波法在隐伏断层探测中的应用研究[J].中国地震局地球物理研究所硕士学位论文. 2007:22~36
32 A. Zerwer, G. Cascante, J. Hutchinson. Parameter Estimation in Finite Element Simulations of Rayleigh Waves[J]. Geotechnical and Geoenvironmental Engineering. 2002,3:250~261
33陈龙珠,严细水,赵永倩.关于面波法检测地基波速中的测点布置问题[J].岩土工程学报. 2003,25(1):63~66
34 Yixian Xu, Jianghai Xia, Richard D. Miller. Quantitative estimation of minimum offset for multichannel surface-wave survey with actively exciting source[J]. Journal of Applied Geophysics. 2006,59:117~125
35 Longzhu Chen, Jinying Zhu, Xishui Yan, Chunyu Song. On arrangement of source and receivers in SASW testing[J]. Soil Dynamics and Earthquake Engineering. 2004,24:389~396
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