低应变反射波法振源特性仿真分析
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摘要
基桩低应变反射波法测试中激振力特性,如脉冲宽度、入射波幅值等,对检测结果的可靠性有重要影响,本文利用有限元软件ANSYS/LS-DYNA对力脉冲宽度影响因素及其对测试效果的影响进行数值模拟。
论文首先简单的阐述了低应变反射波法的基本理论及运用ANSYS/LS-DYNA的建模过程,其次定义了钟形力脉冲宽度,并运用数值模拟得出了钢、铝、尼龙和聚乙烯塑料四种材料手锤的脉冲宽度。重点探讨了接触面积、敲击速度、锤重以及垫片厚度对脉冲宽度的影响规律,得出了以下主要结论：
(1)接触面积越大,激励的力脉冲宽度越小,入射波幅值也越小；
(2)敲击速度对脉冲宽度基本没有影响,但入射波幅值随敲击速度的增大按线性规律增大：
(3)脉冲宽度随激振锤重量的增大按幂函数的关系增大；
(4)锤头材料越厚(垫片厚度越大),力脉冲宽度越大,并且力脉冲宽度随垫片厚度的增大按线性规律增大。
最后应用不同脉冲宽度的激振锤,来验证对测试效果的影响。研究发现钢锤敲击的窄脉冲波对识别桩头附近的缺陷比较有利,而长大桩使用钢锤激振会引起波速下降、波形振荡,但是聚乙烯塑料锤敲击的宽脉冲波能克服上述问题。因此应根据桩的几何尺寸及测试目的,合理调节锤头材质、接触面积、敲击速度、锤重以及垫片厚度来激发合适脉冲宽度的入射波以满足测试的需要。在能够获得桩底反射的前提下,脉冲宽度和敲击速度尽量小。
The impact force character of reflected wave test for low strain, such as pulse width, the incident wave amplitude,have important influence to the reliablity of the test results. Using the finite element program ANSYS/LS-DYNA, this thesis simulated the influence factors of the force pulse width and its effect to the test results.
Firstly,the basic theory of reflected wave test for low strain and the modeling process by applied ANSYS/LS-DYNA are simple described, followed by the definition of a bell-shaped force pulse width. The pulse width of four materials, such as steel, aluminum, nylon and polyethylene plastic are calculated by the numerical simulation. The most important investigation is the Influence of pulse width of contact area, impact velocity, weight of hammer and shim thickness, reached the following conclusions:
(1) the greater the contact area, the smaller the pulse width of impact force, the incident wave amplitude is also smaller;
(2) impact velocity had no effect on the pulse width, but the incident wave amplitude increases with the impact velocity increased by a linear law;
(3) Pulse width increases with the impact vibration hammer weight increases by a power function relationship
(4) Thicker shim, the greater the pulse width,and impact force pulse width with shim thickness increased by a linear law.
Lastly apply a impact hammer with different pulse width to verify the effect of the test. It found that narrow pulse wave which produced by the steel hammer is propitious to identify defects in the vicinity of pile top, whereas steel hammer impact large diameter pile may cause wave speed decreased and wave graph oscillated.At the same time,wide pulse wave which produced by the polyethylene plastic hammer can overcome these problem.So the appropriate pulse width of the incident wave which are adjusted by hammer material,contact area,impact velocity, weight of hammer and shim thickness should be determined according to the geometry size of pile and testing purposes to meet the test requirements.The pulse width and impact velocity as small as possible on the premise that can obtain reflection from the pile toe.
论文首先简单的阐述了低应变反射波法的基本理论及运用ANSYS/LS-DYNA的建模过程,其次定义了钟形力脉冲宽度,并运用数值模拟得出了钢、铝、尼龙和聚乙烯塑料四种材料手锤的脉冲宽度。重点探讨了接触面积、敲击速度、锤重以及垫片厚度对脉冲宽度的影响规律,得出了以下主要结论：
(1)接触面积越大,激励的力脉冲宽度越小,入射波幅值也越小；
(2)敲击速度对脉冲宽度基本没有影响,但入射波幅值随敲击速度的增大按线性规律增大：
(3)脉冲宽度随激振锤重量的增大按幂函数的关系增大；
(4)锤头材料越厚(垫片厚度越大),力脉冲宽度越大,并且力脉冲宽度随垫片厚度的增大按线性规律增大。
最后应用不同脉冲宽度的激振锤,来验证对测试效果的影响。研究发现钢锤敲击的窄脉冲波对识别桩头附近的缺陷比较有利,而长大桩使用钢锤激振会引起波速下降、波形振荡,但是聚乙烯塑料锤敲击的宽脉冲波能克服上述问题。因此应根据桩的几何尺寸及测试目的,合理调节锤头材质、接触面积、敲击速度、锤重以及垫片厚度来激发合适脉冲宽度的入射波以满足测试的需要。在能够获得桩底反射的前提下,脉冲宽度和敲击速度尽量小。
The impact force character of reflected wave test for low strain, such as pulse width, the incident wave amplitude,have important influence to the reliablity of the test results. Using the finite element program ANSYS/LS-DYNA, this thesis simulated the influence factors of the force pulse width and its effect to the test results.
Firstly,the basic theory of reflected wave test for low strain and the modeling process by applied ANSYS/LS-DYNA are simple described, followed by the definition of a bell-shaped force pulse width. The pulse width of four materials, such as steel, aluminum, nylon and polyethylene plastic are calculated by the numerical simulation. The most important investigation is the Influence of pulse width of contact area, impact velocity, weight of hammer and shim thickness, reached the following conclusions:
(1) the greater the contact area, the smaller the pulse width of impact force, the incident wave amplitude is also smaller;
(2) impact velocity had no effect on the pulse width, but the incident wave amplitude increases with the impact velocity increased by a linear law;
(3) Pulse width increases with the impact vibration hammer weight increases by a power function relationship
(4) Thicker shim, the greater the pulse width,and impact force pulse width with shim thickness increased by a linear law.
Lastly apply a impact hammer with different pulse width to verify the effect of the test. It found that narrow pulse wave which produced by the steel hammer is propitious to identify defects in the vicinity of pile top, whereas steel hammer impact large diameter pile may cause wave speed decreased and wave graph oscillated.At the same time,wide pulse wave which produced by the polyethylene plastic hammer can overcome these problem.So the appropriate pulse width of the incident wave which are adjusted by hammer material,contact area,impact velocity, weight of hammer and shim thickness should be determined according to the geometry size of pile and testing purposes to meet the test requirements.The pulse width and impact velocity as small as possible on the premise that can obtain reflection from the pile toe.
引文
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[12]张冬茵LSDYNA在土-结构动力相互作用中的应用[D].中国地震局工程力学研究所工学硕士学位论文,2003
[13]陈波,吕西林,李培振,陈跃庆.用ANSYS模拟结构-地基动力相互作用振动台试验的建模方法[J].地震工程与工程震动,2002(01)：126-131
[14]赵方成.应用LS-DYNA对钢筋混凝土柱破坏的仿真[D].兰州理工大学硕士学位论文,2009
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[21]赵振东.桩基贯入过程的有限元分析[J].地震工程与工程振动,2002,12(1)：50-56
[22]柴华友,贺怀建,唐念慈.桩土相互作用模型及模型实验[J].岩土力学,1993(2)：76-84
[23]陈卫东,柴华友.桩土相互作用对定量分析的影响[J].岩土工程界,2000,4(12)：38-41
[24]卢伟倬.低应变反射波法参数影响分析[D].天津大学硕士研究生学位论文.2003
[25]柯宅邦.基桩低应变动测空间轴对称问题的理论[D].合肥工业大学硕士研究生学位论文,2006
[26]吴庆曾.声测与动测技术[M].北京：中国电力出版社,2009
[27]马洪顺,邢国平.聚乙烯合成塑料管弹性模量等指标测定的试验研究[J].试验技术与试验机,1989(6),10-13
[28]刘屠梅,赵竹占.基桩检测技术与实例[M].北京：中国建筑工业出版社,2006
[29]李德庆,李澄宇,李澄海.桩基工程质量的诊断技术[M].北京：中国建筑工业出版社,2009
[30]张宏.灌注桩检测与处理[M].北京：人民交通出版社,2000
[31]李志成,高乔民.桩基础试验[M].北京：中国林业出版社,2001
[32]朱波,李微.低应变反射波法测桩中的几何弥散效应[J].西南公路2003(2),32-37
[33]黎正根,龚育龄.波在大直径桩中传播的三维效应现象[J].岩石力学与工程学报1998,17(4)：434-439
[34]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[J].岩土工程学报2006,28(5),617-621
[35]Frank Rausche,Fred Moses,George G Goble,Soil Resistance Predictions from Pile Dynamics,Journal of the Soil Mechanics and Foundations Division,1972,98(9):917-937
[36]Robert F Stevens,The use of dynamic pile testing to interpret soil set-up,Practices and Trends in Deep Foundations 2004(GSP No.125),Jerry A.DiMaggio,Mohamad H.Hussein,Editors,Los Angeles,Califor-nia,USA,2004:96-109
[37]雷正辉.低应变反射波法力锤性能的匹配研究[D].广东工业大学硕士研究生学位论文,2007
[38]贺占海.低应变反射波法桩身完整性检测的理论与实践[D].天津大学硕士研究生学位论文,2005
[39]罗文章.管桩在低应变瞬态集中荷载作用下的速度响应研究[D].中国建筑科学研究院硕士研究生学位论文,2002
[40]Seitz J.M.(1992).Pile integrity by low strain impacts-A state-of-the-art. Proceedings of the 4th IC-ASWPT,Hague,Netherlands,pp.627-637
[41]智胜英.时域内低应变基桩缺陷定量分析方法研究[D].天津大学博士研究生学位论文.2008
[42]Zai JinZhang(1988). Pile dynamic testing experiences in Shanghai. Proceedings of the 3rd ICASWPT,Ottawa,Canada,pp.781-792
[43]吴佩江,孙月明,程耀东.脉冲锤垫片特性及其力脉冲波形[J].振动与击,1983(2),58-68
[44]王大为,辛建营,李荣越.桩基检测中提高低应变反射波法准确性的若干方法探讨[J].吉林交通科技,2009(4),43-45
[45]ASTM D5882-07.Standard test method for low strain impact integrity testing of deep foundations.
[46]Hussein M.& Khalaf K.(1994). Low strain testing of dynamic data on the model piles.1994 PDA Users Days,Orlando,USA,Section 20
[47]张献民.时间域中基桩缺陷低应变动测的定量分析[J].土木工程报,2004,37(6)：63-69
[48]吴树昌,李润才,杨庆佛.锤击试验中用响应时域波形确定力脉冲的合适宽度[J].太原工业大学报,1986(3)
[49]周光龙.桩基参数动测法[C].中国土木工程学会第三届土力学及基础工程学术会议论文集.北京,中国建筑工程出版社,1981
[50]陈凡,王仁军.尺寸效应对基桩低应变完整性检测的影响[J].岩土工程学报.1998,20(5)：92-95
[51]周光龙.柱基参数动测法[C].应力波理论在桩基工程中应用论文集.湖南：湖南大学土木系,1986,86-v99
[52]王建华,智胜英.低应变条件下桩土相互作用的阻尼系数[J].岩石力学与工程学报.2007,26(9)：1800-1808
[53]蔡建原,杨泽群,周福霖.淤泥质土中沉管灌注桩的缩颈机理和施对策[J].施工技术.1994(1),26-28
[2]罗骐先.桩基工程检测手册[M].北京：人民交通出版社,2003：61-99
[3]Smith,E.A.L.Pile Driving Analysis by the Wave EquationJourmal of the SoilMechanics and Foundation Division.Proceeding ASCE.Vol.86.No.SM4.August.1960.
[4]Goble G G, et al, Bearing Capacity of Piles from Dynamic Measure, Final Report, Report No.Ohio-DOT-05-77,Ohio Departmentof Transportation,Federal highway administration, Department of Civil engineering,Case Western Reserve University,1975
[5]GRL.Inc.CAPWAPC Manual,1993
[6]Goble G G,et al,Wave Equation Analysis of Pile Driving-EAPProgram.Volumes 1 through 4,FHWA IP-76-13.1 Through IP-76-14.K,April 1976 With an update in march 1981
[7]王雪峰,吴世明.基桩动测技术[M].北京：科学出版社,2004
[8]吴兴序.岩土工程原位测试技术[M].成都：西南交通大学岩土工程系,2008
[9]柳祖亭,顾利平.桩基振动分析与质量监测[M].南京：东南大学出版社,1996
[10]雷林源.桩基动力学[M].北京：冶金工业出版社,2000
[11]王靖涛.桩基应力波的检测理论及工程应用[M].北京：地震出版社,1999
[12]张冬茵LSDYNA在土-结构动力相互作用中的应用[D].中国地震局工程力学研究所工学硕士学位论文,2003
[13]陈波,吕西林,李培振,陈跃庆.用ANSYS模拟结构-地基动力相互作用振动台试验的建模方法[J].地震工程与工程震动,2002(01)：126-131
[14]赵方成.应用LS-DYNA对钢筋混凝土柱破坏的仿真[D].兰州理工大学硕士学位论文,2009
[15]ANSYS/LS-DYNA user's guide[M].ANSYS Inc.1994
[16]ANSYS/LS-DYNA培训手册[M]ANSYS Inc.1998
[17]尚晓江,苏建宇,王化锋ANSYS/LS-DYNA动力分析方法与工程实例[M].北京：中国水利水电出版社,2008
[18]王新敏ANSYS工程结构数值分析[M].北京：人民交通出版社,2007
[19]龚曙光,谢桂花ANSYS操作命令与参数化编程[M].北京：机械工业出版社,2004
[20]许宏发,王斌,戴小平.桩土接触面力学参数取值研究[J].河海大学学报2001(12)：54-56
[21]赵振东.桩基贯入过程的有限元分析[J].地震工程与工程振动,2002,12(1)：50-56
[22]柴华友,贺怀建,唐念慈.桩土相互作用模型及模型实验[J].岩土力学,1993(2)：76-84
[23]陈卫东,柴华友.桩土相互作用对定量分析的影响[J].岩土工程界,2000,4(12)：38-41
[24]卢伟倬.低应变反射波法参数影响分析[D].天津大学硕士研究生学位论文.2003
[25]柯宅邦.基桩低应变动测空间轴对称问题的理论[D].合肥工业大学硕士研究生学位论文,2006
[26]吴庆曾.声测与动测技术[M].北京：中国电力出版社,2009
[27]马洪顺,邢国平.聚乙烯合成塑料管弹性模量等指标测定的试验研究[J].试验技术与试验机,1989(6),10-13
[28]刘屠梅,赵竹占.基桩检测技术与实例[M].北京：中国建筑工业出版社,2006
[29]李德庆,李澄宇,李澄海.桩基工程质量的诊断技术[M].北京：中国建筑工业出版社,2009
[30]张宏.灌注桩检测与处理[M].北京：人民交通出版社,2000
[31]李志成,高乔民.桩基础试验[M].北京：中国林业出版社,2001
[32]朱波,李微.低应变反射波法测桩中的几何弥散效应[J].西南公路2003(2),32-37
[33]黎正根,龚育龄.波在大直径桩中传播的三维效应现象[J].岩石力学与工程学报1998,17(4)：434-439
[34]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[J].岩土工程学报2006,28(5),617-621
[35]Frank Rausche,Fred Moses,George G Goble,Soil Resistance Predictions from Pile Dynamics,Journal of the Soil Mechanics and Foundations Division,1972,98(9):917-937
[36]Robert F Stevens,The use of dynamic pile testing to interpret soil set-up,Practices and Trends in Deep Foundations 2004(GSP No.125),Jerry A.DiMaggio,Mohamad H.Hussein,Editors,Los Angeles,Califor-nia,USA,2004:96-109
[37]雷正辉.低应变反射波法力锤性能的匹配研究[D].广东工业大学硕士研究生学位论文,2007
[38]贺占海.低应变反射波法桩身完整性检测的理论与实践[D].天津大学硕士研究生学位论文,2005
[39]罗文章.管桩在低应变瞬态集中荷载作用下的速度响应研究[D].中国建筑科学研究院硕士研究生学位论文,2002
[40]Seitz J.M.(1992).Pile integrity by low strain impacts-A state-of-the-art. Proceedings of the 4th IC-ASWPT,Hague,Netherlands,pp.627-637
[41]智胜英.时域内低应变基桩缺陷定量分析方法研究[D].天津大学博士研究生学位论文.2008
[42]Zai JinZhang(1988). Pile dynamic testing experiences in Shanghai. Proceedings of the 3rd ICASWPT,Ottawa,Canada,pp.781-792
[43]吴佩江,孙月明,程耀东.脉冲锤垫片特性及其力脉冲波形[J].振动与击,1983(2),58-68
[44]王大为,辛建营,李荣越.桩基检测中提高低应变反射波法准确性的若干方法探讨[J].吉林交通科技,2009(4),43-45
[45]ASTM D5882-07.Standard test method for low strain impact integrity testing of deep foundations.
[46]Hussein M.& Khalaf K.(1994). Low strain testing of dynamic data on the model piles.1994 PDA Users Days,Orlando,USA,Section 20
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