楔形桩的动力响应与试验研究
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摘要
假设桩体为弹性,桩周土体通过平面应变模型描述,利用Laplace变换和阻抗传递法求得桩顶动力响应.对数值结果进行参数分析,讨论了桩土特性对楔形桩动力响应的影响,并且通过模型试验验证了理论的正确性.结果表明:1)存在临界桩径比,使得楔形桩的桩底反射信号难以判读,临界桩径比随桩长增大而增大;2)楔角和桩长对楔形桩的动力响应有较大的影响,对于桩尖直径为0的小直径楔形桩,桩长对其动力响应影响不大;3)土体的剪切波速和纵向分层性对楔形桩的动力响应会产生较大影响;4)模型试验结果与理论解符合,反映规律一致.
The pile was supposed to be elastic and the plane-strain model was adopted to simulate the surrounding soil.By the means of Laplace transform and impedance function transfer method,the dynamic response of tapered pile was obtained.Then,by parametric method,the influence of pile and soil characteristics on the dynamic response of tapered pile was discussed.Meanwhile,the correctness of the theory was verified by model test.The results show that: 1)There is a critical pile diameter ratio at which the reflected signal from pile bottom is difficult to find,and the ratio increases as the pile grows; 2) Cone angle and pile length have a great influence on the dynamic response of tapered pile.However,in the case of small-diameter pile with a zero-diameter end,pile length doesn't have an obvious influence;3) Shear wave velocity of soil and vertical distribution of soil have a great influence on the dynamic response of tapered pile; 4)Good agreement is shown between experimental and theoretical results.
The pile was supposed to be elastic and the plane-strain model was adopted to simulate the surrounding soil.By the means of Laplace transform and impedance function transfer method,the dynamic response of tapered pile was obtained.Then,by parametric method,the influence of pile and soil characteristics on the dynamic response of tapered pile was discussed.Meanwhile,the correctness of the theory was verified by model test.The results show that: 1)There is a critical pile diameter ratio at which the reflected signal from pile bottom is difficult to find,and the ratio increases as the pile grows; 2) Cone angle and pile length have a great influence on the dynamic response of tapered pile.However,in the case of small-diameter pile with a zero-diameter end,pile length doesn't have an obvious influence;3) Shear wave velocity of soil and vertical distribution of soil have a great influence on the dynamic response of tapered pile; 4)Good agreement is shown between experimental and theoretical results.
引文
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[3]刘杰,何杰,闵长青.楔形刚性桩与桩周土的非线性相互作用[J].铁道学报,2010,32(2):137-140.LIU J,HE J,MIN C Q. Nonlinear interaction between the rigid taper pile and pile-surrounding soil[J]. Journal of the China Railway Society,2010,32(2):137—140.(In Chinese)
[4]NOVAK M,ABOUL-ELLA F. Impedance functions of piles in layered media[J].Journal of the Engineering Mechanics Division,1978,104(3):643-661.
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[8]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应用[J].土木工程学报,1998,31(6):56—67.WANG K H,XIE K H,ZENG G X.An analytical solution to forced vibration of foundation pile with variable section impedance and its application[J]. China Civil Engineering Journal,1998,31(6):56—67.(In Chinese)
[9]王奎华,张宏志,李振亚,等.桩底土对既有承台单桩纵向振动特性的影响研究[J].湖南大学学报(自然科学版),2017,44(11):170—176.WANG K H,ZHANG H Z,LI Z Y,et al.Study on influence of pile subsoil on vertical vibration characteristic of single pile with cushion cap[J].Journal of Hunan University(Natural Sciences),2017,44(11):170—176.(In Chinese)
[10]王奎华,高柳,肖偲,等.考虑桩周土竖向作用大直径楔形桩纵向振动特性[J].岩土力学,2016,37(S2):223—231.WANG K H,GAO L,XIAO S,et al.Dynamic characteristic of large diameter tapered pile considering vertical reaction of pile surrounding soil[J]. Rock and Soil Mechanics,2016,37(S2):223—231.(In Chinese)
[11]陈安国,刘东甲.基桩低应变检测的波动方程法数值计算[J].合肥工业大学学报(自然科学版),2007,30(10):1336-1340.CHEN A G,LIU D J.Numerical computation of the wave equation for low strain test piles[J].Journal of Hefei University of Technology(Natural Science),2007,30(10):1336—1340.(In Chinese)
[12]吴文兵,王奎华,武登辉,等.考虑横向惯性效应时楔形桩纵向振动阻抗研究[J].岩石力学与工程学报,2011,30(S2):3618—3625.WU W B,WANG K H,WU D H,et al.Study of dynamic longitudinal impedance of tapered pile considering lateral inertial effect[J].Chinese Journal of Rock Mechanics and Engineering,2011,30(S2):3618—3625.(In Chinese)
[13]吴文兵,王奎华,窦斌.任意层地基中粘弹性楔形桩纵向振动响应研究[J].振动与冲击,2013,32(8):120-127.WU W B,WANG K H,DOU B.Vertical dynamic response of a viscoelastic tapered pile embedded in layered foundation[J].Journal of Vibration and Shock,2013,32(8):120-127.(In Chinese)
[14]吴文兵,谢帮华,黄生根,等.考虑挤土效应时楔形桩纵向振动阻抗研究[J].地震工程学报,2015,37(4):1042—1048.WU W B,XIE B H,HUANG S G,et al. Vertical dynamic impedance of tapered piles considering compacting effects[J].China Earthquake Engineering Journal,2015,37(4):1042—1048.(In Chinese)
[15]张献民,蔡靖,王建华.基桩缺陷逐步能量恢复递推定量分析[J].岩土力学,2003,24(S2):481—484.ZHANG X M,CAI J,WANG J H.Quantitative recurrence analysis to determine defects of piles by energy recovery method[J].Rock and Soil Mechanics,2003,24(S2):481—484.(In Chinese)
[2]KODIKARA J K,MOORE I D. Axial response of tapered piles in cohesive frictional ground[J]. Journal of Geotechnical Engineering,1993,119(4):675-693.
[3]刘杰,何杰,闵长青.楔形刚性桩与桩周土的非线性相互作用[J].铁道学报,2010,32(2):137-140.LIU J,HE J,MIN C Q. Nonlinear interaction between the rigid taper pile and pile-surrounding soil[J]. Journal of the China Railway Society,2010,32(2):137—140.(In Chinese)
[4]NOVAK M,ABOUL-ELLA F. Impedance functions of piles in layered media[J].Journal of the Engineering Mechanics Division,1978,104(3):643-661.
[5]GOUGH W,RICHARDS J P G,WILLIAMS R P,et al. Vibrations and waves[J].Physics Today,1996,49(12):53—54.
[6]KOTEN H V,MIDDENDORP P,BREDERODE P V.An analysis of dissipative wave propagation in a pile[C]//Proceedings of International Seminar on the Application of Stress Wave Theory on Piles.Stockholm,1980:22—40.
[7]郭平.敲击法测桩的波动原理[J].湖南大学学报(自然科学版),1992,19(4):82—88.GUO P.The wave-theoretical principle of the impact method of testing piles[J].Journal of Hunan University(Natural Sciences),1992,19(4):82—88.(In Chinese)
[8]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应用[J].土木工程学报,1998,31(6):56—67.WANG K H,XIE K H,ZENG G X.An analytical solution to forced vibration of foundation pile with variable section impedance and its application[J]. China Civil Engineering Journal,1998,31(6):56—67.(In Chinese)
[9]王奎华,张宏志,李振亚,等.桩底土对既有承台单桩纵向振动特性的影响研究[J].湖南大学学报(自然科学版),2017,44(11):170—176.WANG K H,ZHANG H Z,LI Z Y,et al.Study on influence of pile subsoil on vertical vibration characteristic of single pile with cushion cap[J].Journal of Hunan University(Natural Sciences),2017,44(11):170—176.(In Chinese)
[10]王奎华,高柳,肖偲,等.考虑桩周土竖向作用大直径楔形桩纵向振动特性[J].岩土力学,2016,37(S2):223—231.WANG K H,GAO L,XIAO S,et al.Dynamic characteristic of large diameter tapered pile considering vertical reaction of pile surrounding soil[J]. Rock and Soil Mechanics,2016,37(S2):223—231.(In Chinese)
[11]陈安国,刘东甲.基桩低应变检测的波动方程法数值计算[J].合肥工业大学学报(自然科学版),2007,30(10):1336-1340.CHEN A G,LIU D J.Numerical computation of the wave equation for low strain test piles[J].Journal of Hefei University of Technology(Natural Science),2007,30(10):1336—1340.(In Chinese)
[12]吴文兵,王奎华,武登辉,等.考虑横向惯性效应时楔形桩纵向振动阻抗研究[J].岩石力学与工程学报,2011,30(S2):3618—3625.WU W B,WANG K H,WU D H,et al.Study of dynamic longitudinal impedance of tapered pile considering lateral inertial effect[J].Chinese Journal of Rock Mechanics and Engineering,2011,30(S2):3618—3625.(In Chinese)
[13]吴文兵,王奎华,窦斌.任意层地基中粘弹性楔形桩纵向振动响应研究[J].振动与冲击,2013,32(8):120-127.WU W B,WANG K H,DOU B.Vertical dynamic response of a viscoelastic tapered pile embedded in layered foundation[J].Journal of Vibration and Shock,2013,32(8):120-127.(In Chinese)
[14]吴文兵,谢帮华,黄生根,等.考虑挤土效应时楔形桩纵向振动阻抗研究[J].地震工程学报,2015,37(4):1042—1048.WU W B,XIE B H,HUANG S G,et al. Vertical dynamic impedance of tapered piles considering compacting effects[J].China Earthquake Engineering Journal,2015,37(4):1042—1048.(In Chinese)
[15]张献民,蔡靖,王建华.基桩缺陷逐步能量恢复递推定量分析[J].岩土力学,2003,24(S2):481—484.ZHANG X M,CAI J,WANG J H.Quantitative recurrence analysis to determine defects of piles by energy recovery method[J].Rock and Soil Mechanics,2003,24(S2):481—484.(In Chinese)