路堤穿越既有桥梁的影响研究

论文总字数：24017字

摘 要

Abstract …………………………………………………………………………… Ⅱ

1. 绪论 ……………………………………………………………………………1

1.1 本文的研究背景 ……………………………………………………………1

1.2 问题的提出 …………………………………………………………………2

1.3 国内外研究现状…………………………………………………………………6

1.4 本文的工作………………………………………………………………………6

1.5说明 ……………………………………………………………………………6

1. 侧向堆载下桩破坏机理……………………………………………………………7

2.1侧向堆载下桩土作用机 …………………………………………………………7

2.2 桩-土体系的破坏模式 ………………………………………………………8

1. 有限元软件介绍和模型的建立 ………………………………………………10

3.1有限元计算方法和ABAQUS软件介绍 ……………………………………10

3.2模型建立的工程背景 …………………………………………………………11

3.3 土体本构模型的选择 ………………………………………………………14

3.4模型的建立与相关参数的选择 ………………………………………………15

1. 数值模拟结果及分析 ……………………………………………………… 20

4.1 桩-土体系在路堤堆载下的表现 ……………………………………………20

4.2 路堤高度对桩性状的影响 ………………………………………………… 27

4.3 堆载宽度对桩性状的影响 ………………………………………………… 31

4.4桩体埋深对桩性状的影响 …………………………………………………34

4.5加固措施下路堤堆载对桩基的影响 …………………………………………35

1. 结论与展望 ……………………………………………………………………39

致谢 ……………………………………………………………………………………40

参考文献 ……………………………………………………………………………… 41

路堤穿越既有桥梁的影响研究

中文摘要

桩基础是一种常见的基础形式。临近桩基础的堆载，在地基土工程性质较差的情况下，可能会诱发地基土的侧向位移，进而对桩基础造成附加水平荷载，结构中可能会因此产生内力，桩基础中可能因此诱发桩基承载力下降、桩基剪坏等问题，基于此现象，本文将苏通大桥路堤新建工程中，路堤堆载下的桩基础进行理论研究，并在此基础上，总结规律，为相关工程的施工提出建议。

本文利用ABAQUS 6.11软件进行三维建模实验。分析了路堤堆载对桥梁桩基础的影响。考虑了不同高度、不同宽度的路堤对于不同长度桩的影响，共在27个工况下进行了数值模拟计算。

通过有限元模拟结果中，桩基弯矩、剪力、水平位移和新增沉降四方面结果的提取，初步得到结论：堆载增加时桩身弯矩、剪力显著增加，水平位移和新增沉降增大。堆载宽度增加时，桩各截面的弯矩值都有一定增长，上层土中最大弯矩值增长显著。堆载下桩埋深60m时的性状与埋深80m类似，但与100m时的有显著区别，主要表现为埋深100m时侧移的较大增加。本文还对一种加固措施进行模拟，并验证了这样一种措施具有较好的可行性。

关键词：路堤；堆载；桥梁桩基础；数值模拟

Research on Influence of Existing Pile Foundation

Caused by Threading Embankment

Abstract

Pile foundations is always seen in engineering practice.However, when there is load exerted near the foundation, especially when foundation soil is weak at the same time, the load can trigger lateral movement of foundation soil, and finally exert a lateral pressure on piles.The pressure can cause internal forces in upper construction,as well as decrease in bearing capacity of piles ,even shear failure.Based on the phenomenon, this article is to do some research on pile foundation threaded by embankment in Su Tong Yangtze River Highway Bridge,where a new embankment is about to constructed. With research, this article tries to make some conclusions, and put forward some suggestion in engineering process.

With the help of ABAQUS 6.11 software，a 3-dimensional model is established to conduct the numerical experiment to analyze the influence on pile foundation which caused by threading embankment when the embankment is built up. In this process,the height and width of embankment and the length of pile will be taken in to considerations as factors. Calculation is conducted in 27 working conditions.

With results ,containing moment, sheer, both lateral and vertical displacement of piles, conclusions were brought up. With the increase of height of embankment,sheer and moment of piles rises dramatically and displacement also increase in both direction. When adding width of embankment, increase in moment and sheer are also observed. When buried depth of piles is 60m, the performance of piles is quite different from whose depth is 80m or 100m.However, piles buried in depth of 100m and 80m have little to distinguish from each other.A strengthing method is also calculated, showing good performance against load from embankment.

剩余内容已隐藏，请支付后下载全文，论文总字数：24017字