深厚软土地区高承台桥梁群桩基础水平受力影响因素分析

发布时间：2018-05-11 13:30

本文选题：群桩基础 + 水平受荷桩　；参考：《西南交通大学》2015年硕士论文

【摘要】：高承台群桩基础具有适用条件广泛,承载能力强等特点,在深厚软土地区桥梁工程中得到了广泛的应用。如果设计人员对桥梁群桩基础水平受力影响因素认识不足,可能设计过于保守导致工程造价过高。本文以沪通高速铁路某特大桥群桩基础为背景,主要采用三维有限元方法对深厚软土地层高承台群桩基础水平受力特性的影响因素进行了研究。探讨了桩基水平受力数值分析的建模方法,通过对多种土体本构模型的对比,指出了剑桥粘土模型在本项研究中的适用性；考虑水平受荷桩的桩土界面力学特性,得出适宜的桩土界面处理方法；确定了桩基三维有限元模型几何边界条件的选取原则,即水平方向不宜小于40倍桩径,竖向不宜小于1.3倍桩长。应用ABAQUS有限元软件,采用剑桥粘土本构关系模拟软土,研究了桩长、桩径、桩体刚度、桩顶约束条件、桩间距以及土体参数等因素对高承台桩基水平承载特性的影响规律,结果表明在仅受水平荷载的条件下,其临界桩长约为30倍桩径,桩间距最优值为4倍桩径,剑桥粘土模型中的回弹参数κ对桩基变形起控制作用。最后结合太安特大桥,对其水平承载特性进行了分析。研究成果为水平受力条件下高承台群桩基础的工程设计提供了参考。
[Abstract]:The pile group foundation with high cap is widely used in bridge engineering in deep soft soil area because of its wide applicable conditions and strong bearing capacity. If the designers do not know enough about the influence factors of the horizontal force on the bridge pile group foundation, the design may be too conservative and the project cost is too high. In this paper, based on the foundation of pile group of a large bridge in the Shanghai-Tongtong high-speed railway, the influence factors of the horizontal stress characteristics of the pile group foundation with deep soft soil layer and high cap are studied by using the three-dimensional finite element method. This paper discusses the modeling method of numerical analysis of horizontal force on pile foundation, points out the applicability of Cambridge clay model in this study, and considers the mechanical properties of pile-soil interface of horizontal loaded pile, and points out the applicability of Cambridge clay model in this study through the comparison of various constitutive models of soil. A suitable treatment method of pile-soil interface is obtained, and the selection principle of geometric boundary conditions for 3D finite element model of pile foundation is determined, that is, the horizontal direction should not be less than 40 times the diameter of the pile, and the vertical direction should not be less than 1.3 times the length of the pile. The influence of pile length, pile diameter, pile stiffness, pile top constraint condition, pile spacing and soil parameters on the horizontal bearing characteristics of high cap pile foundation are studied by using the ABAQUS finite element software and the Cambridge clay constitutive relation to simulate the soft soil. The results show that the critical pile length is about 30 times of pile diameter and the optimum value of pile spacing is 4 times under the condition of only horizontal load. The springback parameter 魏 in Cambridge clay model can control the deformation of pile foundation. Finally, the horizontal bearing characteristics of Taian Bridge are analyzed. The research results provide a reference for the engineering design of pile group foundation with high cap under horizontal loading.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U443.15

【参考文献】