【作者】 江小兵；

【导师】 张浩博； 朱沈阳；

【作者基本信息】 西安理工大学 ， 结构工程， 2006， 硕士

【摘要】 目前工程界桩基沉降计算的基本方法为“地基规范”及“桩基规范”，而规范的计算方法理论基础是浅层基础沉降理论，可以说，浅层基础沉降计算的缺点同样带给了桩基沉降计算，从一些文献及本文的分析可以发现，目前桩基沉降计算主要存在如下缺限：1) 浅层基础沉降计算的基本理论是各向同性均质弹性理论，该理论忽略了基础的刚度影响；2) 地基深度确定的不合理；3) 分层土压缩模量E_s的取值问题；4) 现有文献对Geddes解的应用并不合理，无法解决桩侧摩擦阻力呈非线性分布的情况单桩沉降问题。 本文主要针对上述问题，运用弹性理论并结合传统分层总和法对桩基沉降计算进行分析探讨，借助重要数学软件Matlab及有限元计算软件ANSYS对桩基沉降问题进行数值分析和数值模拟分析，得到较多有益于工程实际的结论。 主要工作及结论如下： 1)分析了现行国家规范法计算地基沉降与弹性理论解在理论上的差异以及与工程实测沉降产生偏差的根本原因，阐明了基础宽度、基础埋深、基础刚度、土的泊松比等因素对地基沉降的影响，并证实了基于Mindlin积分解的徐志英解比基于Boussinesq解的积分解合理得多。编制了新的地基变形深度计算程序。 2)当基础尺寸较小、基础刚度较大时，柔性基础与刚性基础的沉降差异较大。 3)通过线积分完整地推导出了桩侧摩阻均匀分布、桩侧摩阻随深度呈线性增加分布以及桩侧摩阻随深度呈任意形状分布的纯摩擦单桩竖向应力及竖向位移的计算公式。 4)在分层总和法基础上提出了一种新的群桩沉降计算模式，并从多方面予以论证，且编制了群桩计算程序。 5)借助通用有限元软件ANSYS模拟分析了摩擦桩、端承桩及摩擦端承桩的沉降性状，ANSYS计算的地基沉降及桩基沉降结果与经典弹性理论计算的结果非常接近，但与弹塑性地基有一定的差距。更多还原

【Abstract】 At present the essential method for the pile foundation settlement calculation are the ground standard and the pile foundation standard in the engineering field, but the base theory of standard computational method is the settlement theory of shallow layer foundation, we can say, the shortcoming of shallow layer foundation settlement computation has taken to the pile foundation settlement computation similarly, from some literature and this article’s analysis we can find, at present the pile foundation settlement calculation mainly existence as follows lacks limits: 1) the elementary settlement calculation theory of shallow layer foundation is the isotropic homogenous theory of elasticity, this theory has neglected the influence of foundation rigidity; 2) the determination of the ground calculation depth is unreasonable; 3) the modulus of compressibility of stratified soil has some problem; 4) the existing literature is unreasonable to the application of Geddes’ solution and unable to solve the settlement calculation problem of the single pile when the skin friction is on non-linear distribution.This article mainly aims at the above question, analyzes and discuss the settlement calculation of the pile foundation by using the theory of elasticity and the traditional layerwise summation method, and carries on the numerical analysis and the value simulation analysis with the aid of the important mathematics software Matlab and the finite element computation software ANSYS, then obtains many conclusion which is beneficial in the actual project.Main work and result as follows:1) Through comparison between layerwise summation method and classical elasticity displacement solution, analyze the difference of calculating foundation settlement between the method of Code for Design of Building Foundation and the theory of elasticity ,so does between calculated and observed settlement Expounds the effect of foundation width embedded depth of foundation and Poisson’s ratio of soil on foundation settlement, and proves that the Xu Zhi-ying’s solution for calculating foundation settlement based on Mindlin’s equation is more perfect than the integral solution based on Boussinesq’s equation. And a new更多还原