桩土相互作用时基桩导纳曲线的仿真分析
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摘要
在基桩完整性检测中,人们常采用时域分析法对实测信号进行分析处理,在很多情况下,由于测试条件、测试技术等方面的原因,单纯的时域分析法难以满足工程检测的需要,在这种情况下就有必要引入频域分析作为时域分析的补充。机械阻抗法是一种以频域分析为主的低应变检测方法。其中稳态机械阻抗法是在桩顶施加一个幅值恒定、频率变化的简谐激振力,以一定的频率间隔在试验频率范围内逐个频率激振,以获取桩顶的速度导纳曲线,此方法具有诸多优点,如单频激振力集中、谐波失真小、频率带宽控制方便、测试精度高,因此易于识别桩的动力特性,已在工程中得到了广泛的应用。
本文采用了一种简化的桩-土动力模型,利用ANSYS软件的谐响应分析功能,得到了完整桩和单一缺陷桩的速度导纳曲线,分析了桩周土体及缺陷程度对速度导纳曲线(基频、基桩嵌固系数、谐振峰频差、峰谷差值)的影响。
鉴于动刚度作为机械阻抗法的一个重要分析指标在检测工程中被错误使用的情况时有发生,本文就桩身尺寸、桩周土、桩身弹性模量、缺陷、特性频率点f M对基桩动刚度的影响进行了单因素分析。
因为本文所采用的计算模型考虑了桩周土的作用,所以文中所得结论对频域分析在基桩完整性及承载力检测与分析方面的应用具有较强的指导意义。
In the foundation pile integrality detecting, the time domain analytical method is usually adopted to analysis process field measured signals. In most cases, due to factors such as test condition, testing technology and so forth, the single time domain analytical method can hardly meet the need of engineering detection. Therefore, in this case, frequency domain analysis is necessary to be introduced as complementarity. The mechanical impedance method is one of the low strain testing methods mainly based on frequency domain analysis. among which the stable mechanical impedance method is the one apply an exciting force of amplitude constancy and frequency variation on the pile, and induce vibration of the pile in a test frequency coverage with a acceptant frequency space in order to obtain the velocity admittance curve of the pile. It has many advantages as follows: 1) it centralizes in single frequency exciting force; 2) it has small probability in harmonic distortion; 3) it is easy to control the frequency bandwidth; 4) the test accuracy is very high. As a result of so many advantages, it is easy to recognize the dynamic characters of the pile, and it has already been widely applied in project.
In this paper a simplified pile-soil dynamic model is adopted and we get the velocity admittance curves of sound piles and single detective piles through the function of harmonic response analysis in the ANSYS software. It also analyzes the influence of the clay around the pile and the defect degree on the velocity admittance curve (including fundamental frequency, foundation pile partial fixing coefficient, resonance peak frequency difference and peak valley difference), and it makes comparative analysis on the impact of both damping and stiffness factor of the soil around the piles on the velocity admittance curve.
In view of the error use of dynamic stiffness as an important analysis indicator in the detection engineering occurs again and again, this thesis makes single factor analysis of the impact of the pile dimension, surrounding soils, pile elastic modulus, defect and characteristic frequency point f M on foundation pile dynamic stiffness.
As the effect of soil around the piles is considered in the calculation model of this paper, the conclusion of this paper directs value in the testing application of stable mechanical impedance method.
本文采用了一种简化的桩-土动力模型,利用ANSYS软件的谐响应分析功能,得到了完整桩和单一缺陷桩的速度导纳曲线,分析了桩周土体及缺陷程度对速度导纳曲线(基频、基桩嵌固系数、谐振峰频差、峰谷差值)的影响。
鉴于动刚度作为机械阻抗法的一个重要分析指标在检测工程中被错误使用的情况时有发生,本文就桩身尺寸、桩周土、桩身弹性模量、缺陷、特性频率点f M对基桩动刚度的影响进行了单因素分析。
因为本文所采用的计算模型考虑了桩周土的作用,所以文中所得结论对频域分析在基桩完整性及承载力检测与分析方面的应用具有较强的指导意义。
In the foundation pile integrality detecting, the time domain analytical method is usually adopted to analysis process field measured signals. In most cases, due to factors such as test condition, testing technology and so forth, the single time domain analytical method can hardly meet the need of engineering detection. Therefore, in this case, frequency domain analysis is necessary to be introduced as complementarity. The mechanical impedance method is one of the low strain testing methods mainly based on frequency domain analysis. among which the stable mechanical impedance method is the one apply an exciting force of amplitude constancy and frequency variation on the pile, and induce vibration of the pile in a test frequency coverage with a acceptant frequency space in order to obtain the velocity admittance curve of the pile. It has many advantages as follows: 1) it centralizes in single frequency exciting force; 2) it has small probability in harmonic distortion; 3) it is easy to control the frequency bandwidth; 4) the test accuracy is very high. As a result of so many advantages, it is easy to recognize the dynamic characters of the pile, and it has already been widely applied in project.
In this paper a simplified pile-soil dynamic model is adopted and we get the velocity admittance curves of sound piles and single detective piles through the function of harmonic response analysis in the ANSYS software. It also analyzes the influence of the clay around the pile and the defect degree on the velocity admittance curve (including fundamental frequency, foundation pile partial fixing coefficient, resonance peak frequency difference and peak valley difference), and it makes comparative analysis on the impact of both damping and stiffness factor of the soil around the piles on the velocity admittance curve.
In view of the error use of dynamic stiffness as an important analysis indicator in the detection engineering occurs again and again, this thesis makes single factor analysis of the impact of the pile dimension, surrounding soils, pile elastic modulus, defect and characteristic frequency point f M on foundation pile dynamic stiffness.
As the effect of soil around the piles is considered in the calculation model of this paper, the conclusion of this paper directs value in the testing application of stable mechanical impedance method.
引文
[1]中华人民共和国行业标准.建筑基桩检测技术规范(JGJ106-2003).北京:中国建筑工业出版社,2003.
[2] Isaacs D V. Reinforced Concrete Pile Formulae. Transactions of the Institute of Engineers, 1931, 370(7): 312-323.
[3] Fox E N. Stress Phenomena Occurring in Pile Driving. Engineering, 1932, 134(9): 214-220.
[4] Kanschin A A, Plutalow A A. On the Computation of Piles, Based on the Theory of Axial Impact. In: Proceedings, First International Conference on Soil Mechanics and Foundation Engineering. Boston, 1936.
[5] Smith E A. Pile Driving Analysis by the Wave Equation. Journal of the Soil Mechanics and Foundation Division. Proceedings ASCE, 1960, 86(4): 141-145.
[6] Davis A G.. From Theory to Field Experience with the Non-destructive Vibration Testing of Piles, Proc. institution of Civil Engineer, Part 2, No.57, 1974.
[7] Novak M. Dynamic Stiffness and Damping of Piles, Canadian Geotechnical Journal, Vol 11, No.4, 1974.
[8] Hussein M H, Goble G.G. A Brief History of the Application of Stress-Wave Theory to Piles. Current Practices and Future Trends in Deep Foundations, 2004. 186-201.
[9] Goble G G, et al. Dynamic Studies on the Bearing Capacity of Piles, PhaseⅢ, Report No.48, Division of Soil Mechanics, Structure and Mechanical Design. Case Western Reserve University. 1970.
[10] Goble G G, et al. Bearing Capacity of Piles from Dynamic Measure, Final. Report No. OHIO-DOT-05-75, Ohio Department of Transportation, Department of Soil Mechanics. Structure and Mechanical Design. Case Western Reserve University.March, 1975.
[11] Goble G G, et al. Wave Equation Analysis of Pile Driving-WEAP Program. Volumes 1 through 4, FHWA IP-76-13, 1 through IP-76-14.K.April 1976 With an Update in March 1981 2003.5.
[12] Middendorp P & Van Brederode P. A Field Monitoring Technique for the Integrity Testing of Foundation Piles, Int. Symposium on Field Measurements in Geomechanics, Zurich, 1983.
[13] Reiding F J & Middendorp P, et al. A Digital Approach to Sonic Poil Testing, Proc of 2nd Int. Conf on the Application of Stress-wave Theory to Piles, Stockholm, 1984
[14] Van Weele, A F, Middendorp P & Reiding F J. Detection of Pile Defects with Digital Integrity Testing Equipment, Foundations and Tunnels, London, 1987.
[15] Rausche F, Likins G & Hussein M. Pile Integrity by low and High Strain Impacts, Proc of 3rd Int.Conf on the Application Stress-wave Theory to piles, Ottawa, Canada, 1988.
[16]周光龙.桩基参数动测法.中国土木工程学会第三届土力学及基础工程学会会议论文选集.北京:中国建筑出版社, 1981.
[17]唐念慈.渤海12号平台钢管桩试验研究.海洋石油, 1979,(3).
[18]蒋泽汉.机械阻抗法无损检验桩身质量.桩基工程学会会议论文集, 1981.
[19]李达祥,张用谦.检测桩质量的水电效应法.冶金建筑, 1982, (2): 140-145.
[20]陈凡. FEIPWAPC特征线桩基波动分析程序.岩土工程学报, 1990, 12(4): 42-48.
[21]王雪峰,吴世明.基桩动测技术.北京:科学出版社,2001.
[22]王雪峰等,扭剪法基本原理及应用,《环境岩土工程理论与实践》,上海:同济大学出版社,2001.6.
[23] Gough W, Richards J P G, Williams R P.Vibration and Waves. Hassled Press of John Wiley & Sons, 1983.
[24]张阿舟,赵淳生.桩基故障诊断理论分析.振动测试与诊断, 1991, (2): 1-8.
[25] Koten H Van, Middendorp P, Brederode P Van.An Anslysis of Dissipative Wave Propagation in a Pile. International Seminar on the Application of Stress WaveTheory on Pile/Stockholm, 1980.
[26]郑灿堂,王杨,许尚杰等.稳态机械阻抗法动测单桩承载力.水利水电技术,1997,28(8):50-52.
[27]刘东甲,卢勤海,陈晓龙等.层状土中多缺陷桩的导纳曲线计算及初步应用.水文地质工程地质,2001,(6):18-19.
[28]刘东甲.不均匀土中多缺陷桩的轴向动力响应.岩土工程学报,2000,22(4):391-395.
[29]王腾,王奎华,谢康和.变界面桩速度导纳的解析解.岩石力学与工程学报,2004,21(4):573-576.
[30]胡昌斌,王奎华,谢康和.考虑桩土耦合作用时弹性支承桩纵向振动特性分析及应用.工程力学,2003,20(2):146-154.
[31] [30]蔡靖,张献民,王建华.基桩完整性检测中桩土相互作用参数的试验研究.岩土工程学报,2006,20(28):617-621.
[32]冯世进,陈云敏,刘明振.成层土中粘弹性桩纵向振动分析及工程应用.中国公路学报,2004,17(2):59-63.
[33]王奎华,谢康和,曾国熙.有限长桩受迫振动问题解析解及其应用.岩土工程学报, 1997, 19(6): 27-35.
[34]王奎华.桩材料阻尼对动测曲线的影响研究.岩土力学, 1998, 19(4):41-47.
[35]王奎华,谢康和,曾国熙.变截面阻抗桩受迫振动问题解析解及其应用.土木工程学报, 1998, 31(6): 545-551.
[36]王奎华.考虑桩体粘性的变阻抗桩受迫振动问题解析解.振动工程学报, 1999, 12(4): 513-520.
[37]王雪峰,吴世明,杨人禄等.小扰动状态下桩的振动特性.岩石力学与工程学报,2002,21(12):1881-1885.
[38]阙任波,王奎华.考虑土体三维波动效应时弹性支承桩的振动理论及其应用.计算力学学报,2005,22(6):658-664.
[39]赵振东,杉木三千雄,铃木善雄.桩基低应变完整性检测的分析研究.地震工程与工程振动, 1995(4): 104-112.
[40]陶莉,袁越,穆荣.土阻力对低应变动测影响的计算机仿真分析.振动、测试与诊断, 2000, 20(2): 115-118.
[41]陈芬.基桩动测频域分析仿真研究:[华中科技大学学士学位论文].武汉:华中科技大学,2005.
[42]孔煊.基于ANSYS的基桩动力响应三维分析:[华中科技大学学士学位论文].武汉:华中科技大学,2006.
[43]吴娟.基于ANSYS的基桩动力响应三维分析:[华中科技大学学士学位论文].武汉:华中科技大学,2006.
[44]罗骐先.基桩工程检测手册.北京:人民交通出版社,2004.
[45]吴静慧.框架结构、单桩承台基础、地基共同作用分析:[燕山大学硕士学位论文].秦皇岛:燕山大学,2006.
[46] RAUSCHE F. Stress wave measuring in practice[A]. The Second International Conference on the Application of Stress-Wave Theory on Piles[C]. Stockholm: Publisher A.A., 1984.1 23.
[47] LYSMER J, RICHART F E. Dynamic response of footing to vertical load [J]. J.Soil Mech. and Found Div., ASCE, 1966, 2(1): 65-90.
[48]屠勰.桩基垂直振动动力特性研究:[同济大学硕士学位论文].上海:同济大学,2003.
[49]曾利民.论用动刚度计算单桩承载力的不确定性.建筑结构学报,1998, 19(4):61-66.
[2] Isaacs D V. Reinforced Concrete Pile Formulae. Transactions of the Institute of Engineers, 1931, 370(7): 312-323.
[3] Fox E N. Stress Phenomena Occurring in Pile Driving. Engineering, 1932, 134(9): 214-220.
[4] Kanschin A A, Plutalow A A. On the Computation of Piles, Based on the Theory of Axial Impact. In: Proceedings, First International Conference on Soil Mechanics and Foundation Engineering. Boston, 1936.
[5] Smith E A. Pile Driving Analysis by the Wave Equation. Journal of the Soil Mechanics and Foundation Division. Proceedings ASCE, 1960, 86(4): 141-145.
[6] Davis A G.. From Theory to Field Experience with the Non-destructive Vibration Testing of Piles, Proc. institution of Civil Engineer, Part 2, No.57, 1974.
[7] Novak M. Dynamic Stiffness and Damping of Piles, Canadian Geotechnical Journal, Vol 11, No.4, 1974.
[8] Hussein M H, Goble G.G. A Brief History of the Application of Stress-Wave Theory to Piles. Current Practices and Future Trends in Deep Foundations, 2004. 186-201.
[9] Goble G G, et al. Dynamic Studies on the Bearing Capacity of Piles, PhaseⅢ, Report No.48, Division of Soil Mechanics, Structure and Mechanical Design. Case Western Reserve University. 1970.
[10] Goble G G, et al. Bearing Capacity of Piles from Dynamic Measure, Final. Report No. OHIO-DOT-05-75, Ohio Department of Transportation, Department of Soil Mechanics. Structure and Mechanical Design. Case Western Reserve University.March, 1975.
[11] Goble G G, et al. Wave Equation Analysis of Pile Driving-WEAP Program. Volumes 1 through 4, FHWA IP-76-13, 1 through IP-76-14.K.April 1976 With an Update in March 1981 2003.5.
[12] Middendorp P & Van Brederode P. A Field Monitoring Technique for the Integrity Testing of Foundation Piles, Int. Symposium on Field Measurements in Geomechanics, Zurich, 1983.
[13] Reiding F J & Middendorp P, et al. A Digital Approach to Sonic Poil Testing, Proc of 2nd Int. Conf on the Application of Stress-wave Theory to Piles, Stockholm, 1984
[14] Van Weele, A F, Middendorp P & Reiding F J. Detection of Pile Defects with Digital Integrity Testing Equipment, Foundations and Tunnels, London, 1987.
[15] Rausche F, Likins G & Hussein M. Pile Integrity by low and High Strain Impacts, Proc of 3rd Int.Conf on the Application Stress-wave Theory to piles, Ottawa, Canada, 1988.
[16]周光龙.桩基参数动测法.中国土木工程学会第三届土力学及基础工程学会会议论文选集.北京:中国建筑出版社, 1981.
[17]唐念慈.渤海12号平台钢管桩试验研究.海洋石油, 1979,(3).
[18]蒋泽汉.机械阻抗法无损检验桩身质量.桩基工程学会会议论文集, 1981.
[19]李达祥,张用谦.检测桩质量的水电效应法.冶金建筑, 1982, (2): 140-145.
[20]陈凡. FEIPWAPC特征线桩基波动分析程序.岩土工程学报, 1990, 12(4): 42-48.
[21]王雪峰,吴世明.基桩动测技术.北京:科学出版社,2001.
[22]王雪峰等,扭剪法基本原理及应用,《环境岩土工程理论与实践》,上海:同济大学出版社,2001.6.
[23] Gough W, Richards J P G, Williams R P.Vibration and Waves. Hassled Press of John Wiley & Sons, 1983.
[24]张阿舟,赵淳生.桩基故障诊断理论分析.振动测试与诊断, 1991, (2): 1-8.
[25] Koten H Van, Middendorp P, Brederode P Van.An Anslysis of Dissipative Wave Propagation in a Pile. International Seminar on the Application of Stress WaveTheory on Pile/Stockholm, 1980.
[26]郑灿堂,王杨,许尚杰等.稳态机械阻抗法动测单桩承载力.水利水电技术,1997,28(8):50-52.
[27]刘东甲,卢勤海,陈晓龙等.层状土中多缺陷桩的导纳曲线计算及初步应用.水文地质工程地质,2001,(6):18-19.
[28]刘东甲.不均匀土中多缺陷桩的轴向动力响应.岩土工程学报,2000,22(4):391-395.
[29]王腾,王奎华,谢康和.变界面桩速度导纳的解析解.岩石力学与工程学报,2004,21(4):573-576.
[30]胡昌斌,王奎华,谢康和.考虑桩土耦合作用时弹性支承桩纵向振动特性分析及应用.工程力学,2003,20(2):146-154.
[31] [30]蔡靖,张献民,王建华.基桩完整性检测中桩土相互作用参数的试验研究.岩土工程学报,2006,20(28):617-621.
[32]冯世进,陈云敏,刘明振.成层土中粘弹性桩纵向振动分析及工程应用.中国公路学报,2004,17(2):59-63.
[33]王奎华,谢康和,曾国熙.有限长桩受迫振动问题解析解及其应用.岩土工程学报, 1997, 19(6): 27-35.
[34]王奎华.桩材料阻尼对动测曲线的影响研究.岩土力学, 1998, 19(4):41-47.
[35]王奎华,谢康和,曾国熙.变截面阻抗桩受迫振动问题解析解及其应用.土木工程学报, 1998, 31(6): 545-551.
[36]王奎华.考虑桩体粘性的变阻抗桩受迫振动问题解析解.振动工程学报, 1999, 12(4): 513-520.
[37]王雪峰,吴世明,杨人禄等.小扰动状态下桩的振动特性.岩石力学与工程学报,2002,21(12):1881-1885.
[38]阙任波,王奎华.考虑土体三维波动效应时弹性支承桩的振动理论及其应用.计算力学学报,2005,22(6):658-664.
[39]赵振东,杉木三千雄,铃木善雄.桩基低应变完整性检测的分析研究.地震工程与工程振动, 1995(4): 104-112.
[40]陶莉,袁越,穆荣.土阻力对低应变动测影响的计算机仿真分析.振动、测试与诊断, 2000, 20(2): 115-118.
[41]陈芬.基桩动测频域分析仿真研究:[华中科技大学学士学位论文].武汉:华中科技大学,2005.
[42]孔煊.基于ANSYS的基桩动力响应三维分析:[华中科技大学学士学位论文].武汉:华中科技大学,2006.
[43]吴娟.基于ANSYS的基桩动力响应三维分析:[华中科技大学学士学位论文].武汉:华中科技大学,2006.
[44]罗骐先.基桩工程检测手册.北京:人民交通出版社,2004.
[45]吴静慧.框架结构、单桩承台基础、地基共同作用分析:[燕山大学硕士学位论文].秦皇岛:燕山大学,2006.
[46] RAUSCHE F. Stress wave measuring in practice[A]. The Second International Conference on the Application of Stress-Wave Theory on Piles[C]. Stockholm: Publisher A.A., 1984.1 23.
[47] LYSMER J, RICHART F E. Dynamic response of footing to vertical load [J]. J.Soil Mech. and Found Div., ASCE, 1966, 2(1): 65-90.
[48]屠勰.桩基垂直振动动力特性研究:[同济大学硕士学位论文].上海:同济大学,2003.
[49]曾利民.论用动刚度计算单桩承载力的不确定性.建筑结构学报,1998, 19(4):61-66.