苏州二号线地铁穿桥桥梁评估及加固设计

论文总字数：39558字

摘 要

当前我国地铁规模发展迅速，在隧道掘进过程中常常遇到桥梁桩基础侵入盾构区间的情况，会影响桥梁上下部结构、盾构机及隧道的安全性，故需要采取相应加固措施来确保桥梁与盾构的安全。

苏州地铁2号线在下穿广济桥时，需要切削其16根桩基，本文对广济桥进行了全面的检测评估，确定了切削桩基对广济桥安全性的影响程度，并设计了加固方案。

首先检测桥梁的各项状况，检测的内容包括桥梁外观以及钢筋混凝土构件的各项性能，并根据检测结果计算了各项检算系数。先计算原桥的承载能力，再在无桩条件下对每个墩台桩基被切削后的安全性进行分析。利用桥梁博士对原桥与切削桩基后的桥梁墩台建模，并进行验算。依据检测和验算结果撰写检测报告。

结合广济桥现状及盾构影响范围，提出了两种加固方案(扩大基础辅以地基加固法、盖梁预应力加固法)，利用桥梁博士模拟、验算两种加固方法。综合考虑施工成本、创新性等因素，对两种加固方案进行比选，最终选择更新颖的盖梁预应力加固方案。

关键词：地铁穿桥；桥梁检测；桥梁评估；扩大基础；预应力加固

Abstract

At present, the scale of subway in China is developing rapidly. In the process of tunneling, it is often encountered that the pile foundations of a bridge intrude into the shield tunneling section, which will affect the safety of the upper and lower structure of the bridge, the shield tunneling machine and the tunnel. Therefore, it is necessary to take corresponding reinforcement measures to ensure the safety of the bridge and the shield.

When the Suzhou metro line 2 undergoes Guangji Bridge, 16 piles foundations need to be cut off. This paper makes a thorough inspection and evaluation of Guangji Bridge to determine the influence of cutting off pile foundations on its safety, and designs two reinforcement schemes.

Firstly, the conditions of Guangji Bridge are tested, including appearance of the bridge and the performance of reinforced concrete members. The bearing capacity of the original bridge is calculated first, and then the safety of each abutment after cutting off the pile foundations is analyzed in the condition of no pile. The original bridge and the bridge after cutting off pile foundations are both modeled and calculated by Dr. Bridge. Then, a test report is written according to the test and the calculation result.

Considering the current situation of Guangji Bridge and the influence range of shield tunneling, two reinforcement schemes are put forward (Expanded foundation supplemented by foundation reinforcement and Pre-stressed reinforcement of bent caps). Using Dr. Bridge to simulate and calculate these two schemes. The schemes are compared from the aspects of construction cost and innovation. Finally, the more innovative method of Pre-stressed reinforcement is selected to reinforce the bridge.

KEY WORDS: Metro Bridge Crossing, Bridge Detection, Bridge Evaluation, Expanding Foundation, Pre-stressed Reinforcement

目 录

摘要 I

Abstract I

第一章 绪论 1

1.1引言 1

1.2既有案例总结 1

1.3桥梁加固常用方法 2

1.3.1扩大基础法 2

1.3.2增补桩基法 2

1.3.3盖梁加固法 2

1.3.4地基加固辅助工法 2

第二章 工程概况 3

2.1工程背景 3

2.2桥梁概况 3

2.3技术标准 5

2.4项目概况 5

2.5地质条件 6

第三章 桥梁检测与评估 7

3.1桥梁检测依据 7

3.2构件编码规则 7

3.3桥梁外观检测 7

3.3.1桥梁外观检测依据 7

3.3.2桥梁主要外观缺损 7

3.3.3外观检查结论 9

3.4桥梁材质检测 9

3.4.1混凝土碳化深度检测 9

3.4.2混凝土强度检测 10

3.4.3钢筋保护层厚度检测 11

3.4.4钢筋锈蚀状况检测 12

3.4.5混凝土电阻率检测 13

3.5桥梁使用环境调查 13

3.6桥梁防、排水设施调查 14

3.7基于检测结果的承载能力评估方法 14

3.7.1评估方法 14

3.7.2折损系数取值 14

3.8评估结果 18

第四章 墩台安全性分析 19

4.1荷载计算 19

4.1.1上部恒载计算 19

4.1.2下部恒载计算 19

4.1.3活载计算 19

4.2荷载作用 20

4.2.1荷载对桥台作用 20

4.2.2荷载对桥墩作用 20

4.3计算模型 21

4.3.1原桥计算模型 21

4.3.2切削桩基后计算模型 21

4.4原桥下部结构承载能力验算 22

4.4.1桥台承载能力验算 22

4.4.2桥墩承载能力验算 23

4.5切削桩基后承载能力验算 24

4.5.1桥台承载能力验算 24

4.5.2桥墩承载能力验算 26

4.6分析结果 28

第五章 加固方案设计 29

5.1扩大基础法 29

5.1.1方案概述 29

5.1.2分析验算 31

5.2盖梁预应力加固法 36

5.2.1方案概述 36

5.2.2分析验算 37

5.3方案比选 43

结论与展望 44

参考文献（References） 45

致谢 46

附录I：回弹法结构或构件混凝土强度计算表 47

第一章 绪论

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