偏心瞬态激振下基桩横向和竖向振动分析  

Lateral and vertical vibrations of a pile subjected to eccentric transient excitation

作　　者：卢志堂[1] 王志亮[2] 柯宅邦 熊峰 刘东甲[1] 谭晓慧[1] LU Zhi-tang;WANG Zhi-liang;KE Zhai-bang;XIONG Feng;LIU Dong-jia;TAN Xiao-hui(School of Resources and Environmental Engineering,Hefei University of Technology,Hefei 230009,China;School of Civil and Hydraulic Engineering,Hefei University of Technology,Hefei 230009,China;Anhui Key Laboratory of Green Building and Assembly Construction,Hefei 230031,China)

机构地区：[1]合肥工业大学资源与环境工程学院,安徽合肥230009 [2]合肥工业大学土木与水利工程学院,安徽合肥230009 [3]绿色建筑与装配式建造安徽省重点实验室,安徽合肥230032

出　　处：《岩土工程学报》2022年第9期1751-1759,F0002,共10页Chinese Journal of Geotechnical Engineering

基　　金：安徽省住房城乡建设科学技术计划项目(2018YF-010);安徽建工集团有限公司科研项目(2017-10-JF);国家自然科学基金项目(41807266,U1965101,41972278)。

摘　　要：为研究偏心激振下基桩的横向和竖向振动响应,先分别开展了Bernoulli-Euler(BE)梁理论计算和三维数值模拟,并将计算结果与模型桩测试数据进行了对比验证;接着,分析了桩顶横向速度响应特征,探讨其与竖向速度的差异;最后,细究了横截面尺寸与形状、脉冲宽度、桩长、土体刚度、竖向狭长缺陷等因素对桩顶横向振动速度的影响,评价了BE梁模型和三维数值模型的适用性。结果表明:在偏心激振下,桩底反射弯曲波以群波形式到达桩顶,初至反射弯曲波波速接近于横波波速;除纵向波外,弯曲波传播也会引发基桩的竖向振动;随着土体刚度增大,桩底反射弯曲波强度降低,而且衰减程度比纵向波严重;弯曲波遇到竖向狭长缺陷会发生明显反射。研究还发现采取竖向偏心激振方式并依据桩顶横向振动速度,有利于准确检测基桩的完整性。To investigate the lateral and vertical vibration responses of the pile under eccentric transient excitation, the theoretical calculation based on the Bernoulli-Euler(BE) beam theory and the three-dimensional(3D) numerical simulation are first carried out respectively, and the calculated results are compared with the test data of the model pile to verify their rationality. Then, the characteristics of the lateral velocity response on the pile-top are analyzed, and the differences between the lateral and vertical velocities are discussed. Finally, the influences of the cross-section size and shape, pulse width, pile length,soil stiffness and vertical narrow defects on the lateral vibration velocity of the pile-top are studied, and the applicability of the BE beam model and 3D numerical model is evaluated. The results show that when the eccentric excitation is applied, the flexural waves reflected from the pile-toe reach the pile-top in the form of group waves, and the propagation velocity of the first arrival reflected waves is close to that of the shear waves. In addition to that of the longitudinal waves, the propagation of the flexural waves can also trigger vertical vibration of the pile. With an increase in the stiffness of the surrounding soil, the strength of the reflected flexural waves caused by the pile-toe decreases, and the attenuation of the flexural waves is severer than that of the longitudinal waves. The flexural waves can be significantly reflected when they encounter the vertical narrow defect. It is also found that the vertical eccentric excitation method and the use of the lateral vibration velocity of the pile-top are beneficial to accurately detecting the pile integrity.

关 键 词：偏心激振 BE梁 三维数值解 弯曲波 竖向狭长缺陷 

分 类 号：TU473.1[建筑科学—结构工程]