基于土塞效应的大直径管桩纵向振动特性研究

Soil plugging effect-based study on longitudinal vibration characteristics of large-diameter pipe pile

基于广义Voigt模型和附加质量方法,开展了土塞效应对大直径管桩的纵向振动特性影响的研究。根据管桩侧土和端土的分层特点,将整个大直径管桩土体系统沿桩体纵向划分有限微元段,借此利用虚土桩法和附加质量法建立大直径管桩系统的纵向自由振动方程。结合管桩土的耦合条件,利用Laplace变换原理和阻抗传函法则,求解在土塞效应作用下大直径管桩纵向自由振动的桩顶速度的解析解。此外,本文通过对附加质量法模型下的广义Voigt模型参数的敏感区间进行分析,并利用该解的退化曲线和研究资料进行比对来论证本文模型的合理性。最后,通过模型参数对桩顶复阻抗和土塞效应对桩段的综合波速的影响分析,验证本文模型解的合理性,为土塞效应下大直径管桩纵向振动特性研究提供一定的理论支撑。

Based on the generalized Voigt model and the additional mass method,the study on the soil plugging effect on the longitudinal vibration characteristics of large-diameter pipe pile is made herein.In accordance with the characteristics of the layered characteristics of the side soil and end soil of the pipe pile,the entire large-diameter pipe pile soil system is divided into finite micro-element segments along the longitudinal direction of the pile body,from which a longitudinal free vibration equation of the large-diameter pipe pile is established by means of virtual soil pile method and additional mass method.Combined with the coupling condition of pipe pile soil,the analytical solution of the pile-top velocity of the longitudinal free vibration of the large-diameter pipe pile under the soil plugging effect is solved with the principle of Laplace transformation and the impedance transfer rule.Additionally,the reasonability of the model given herein is demonstrated through the analysis made on the sensitivity intervals of the generalized Voigt model parameters under the condition of the additional mass method-based model as well as the degenerated curve of the solution and the relevant study data.Finally,through the analysis on the influences from the model parameters on the complex impedance of pile top and the soil plugging effect on the comprehensive wave velocity of the pile segment,the reasonability of the model solution given herein is verified,and then provides a certain theoretical support for the study on the longitudinal vibration characteristics of large-diameter pipe pile under the soil plug effect.