层状地基中大直径端承桩的竖向振动特性研究  

VERTICAL VIBRATION CHARACTERISTICS OF LARGE-DIAMETER END-BEARING PILE IN LAYERED SOIL

作　　者：任青[1] 高战士 吕洪勇[1] 

机构地区：[1]上海理工大学土木工程系,上海200093

出　　处：《岩石力学与工程学报》2014年第A02期4193-4202,共10页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(51008194)

摘　　要：大直径端承桩广泛地应用于近海工程和高层建筑中,首先总结了经典土体振动平面应变模型的局限性,在此基础上提出改进模型,通过合理选择参数,使得改进模型可以考虑土体水平振动对于竖向振动的影响,通过与经典解的比较,证明了本文解的合理性。然后,将改进的土体振动模型应用于大直径端承桩的竖向振动分析中,给出层状地基中大直径端承桩的动阻抗和动内力。通过分析得出,长细比、土体泊松比和桩–土相对刚度是影响大直径桩动力阻抗的主要因素。最后,将本文模型用于分析近海工程大直径桩基础的动力频响特性,计算结果与三维有限元解一致,说明本文模型能够更为准确地预测大直径桩的振动特性。Large-diameter end-bearing pile is widely used in offshore engineering and high-rise building. The classical plane-strain model of soil is reviewed and its limitations are discussed. An improved model is developed on the basis of plane strain model,which can consider the coincidence of lateral and vertical vibration. The proposed model is proved to be correct after comparing with classical solutions. And then,the above model is introduced into vertical vibration model to discuss dynamic impedance and axial force of large-diameter end-bearing pile in layered soils. After analysis of the slenderness ratio,hysteretic damping ratio,soil Poisson＇s ratio,pile-soil relative stiffness and pile-soil relative density,it can be concluded that slenderness ratio,soil Poisson＇s ratio and pile-soil relative stiffness are the key factors for dynamic impedance of large-diameter end-bearing pile. Finally,the present model is supported by three-dimensional finite element method in predicting dynamic response of large diameter monopile foundations used in offshore wind farm and cross-sea bridge,which shows that the present model can give more reasonable guidance on vibration of large-diameter end-bearing pile.

关 键 词：桩基础 大直径桩 平面应变 传递矩阵法 动力响应 

分 类 号：TU473[建筑科学—结构工程]