论文总字数：41898字

摘 要

为了缓解快速增长的人口带来的巨大的交通出行压力，地铁成为全国乃至全球大中型城市的主要交通方式。而盾构法由于具有其它施工方法所不具备的巨大优势受到了国内外众多工程师的推崇。不仅施工过程不受天气的限制，施工地段可以穿越江河湖海，而且适用的地层范围很广，在软土、软岩地区均可使用盾构法进行施工。但盾构法受其施工原理的影响，必然会造成一定程度的地表沉降。当地表沉降超过规范的允许值时，就有可能造成人财损失。所以，研究盾构开挖引起地表沉降的机理和发展规律，找出影响地表沉降大小的因素，针对性地提出地表沉降的控制措施是十分必要的。

本文在查阅文献的基础上，总结了当前国内外关于盾构开挖引起地表沉降的研究现状，阐述了盾构法尤其是土压平衡盾构的施工原理、适用范围和施工工序，并定性分析了盾构法中地表沉降的产生机理与影响因素。

依托佛山地铁2号线登州站~花卉世界站区间工程，通过对施工过程中地表沉降实测数据的分析，总结了盾构开挖引起地表沉降的发展规律。研究内容及结论如下：

1. 横向地表沉降曲线基本符合Peck提出的高斯分布，横断面最大沉降值在隧道轴线正上方的地表测得，并且同一横断面上离轴线越远的测点，测得的地表沉降值越小。
2. 利用Origin软件对横向地表沉降曲线进行GuassAmp拟合，得出了可用于预测本施工区段地表沉降的Peck公式参数的取值范围。沉降槽宽度系数参数k取值在从0.4到0.6的范围内，地层损失率v取值在从0.5%到0.65%的范围内。
3. 纵向地表沉降开挖顺序可大致分为三个阶段：盾构通过前、盾构通过时与盾构通过后。盾构到达开挖面前15m左右第一阶段的沉降开始，这一阶段的沉降占总沉降的10%至20%；第二阶段的沉降从盾构机到达开挖面时开始，这一阶段的沉降约占总沉降的50%。盾构通过开挖面30m后第三阶段开始，这一阶段的沉降主要由土体的固结作用产生，占总沉降的30%至40%。
4. 本文还专门研究了上覆土层厚度、不同断面的岩体条件和开挖时间三个因素对地表沉降的影响。针对地表沉降产生的各种原因，给出了相应的控制措施。

关键词：盾构法；地表沉降；数据分析；控制措施

Abstract

In order to alleviate the great traffic pressure caused by the explosion of population, the metro becomes the main means of transportation in large and medium-sized cities nationally even globally. The shield method is highly praised by many domestic and foreign engineers because of its great advantages which are not possessed by other construction methods. Not only the construction process is not restricted by weather conditions, shield method can also be applied to construction sites which passing through the rivers. And the applicable strata ranges from soft soil to rock stratum. However, limited by its construction principle, shield method will result in a certain degree of ground surface settlement inevitably. When the surface settlement exceeds the allowable value, it is possible to cause the loss of lives and wealth. Therefore, it is necessary to study the mechanism and development law of ground surface settlement caused by shield method. It’s urgent to find out the factors affecting the surface subsidence and to put forward measures to control ground settlement.

On the basis of literature consultant, the current research situation of surface settlement caused by shield method is summed up in this paper. The construction principle, application scope and construction procedure of shield method is also explained. Mechanism and influencing factors of surface settlement are proved by qualitative analyses.

Based on the interval project from Dengzhou station to the Flower World station of Foshan metro line 2, the laws of ground surface settlement caused by shield method is summarized by the analysis of measured data during the construction process. The research contents and conclusions are as follows:

(1) The curve of horizontal surface settlement accords with the Gaussian distribution proposed by Peck basically. The maximum settlement value is measured on the surface of the tunnel axis. The farther from the axis, the smaller settlement value is measured.

(2) GuassAmp curve is used for fitting measured settlement value by using Origin software. The range of Peck formula parameters which can be used to predict surface settlement in this interval project is obtained. The range of the parameter k of is 0.4 to 0.6, and the range of the loss rate v is 0.5% to 0.65%.

(3) According to the excavation sequence, longitudinal ground surface settlement can be roughly divided into three stages: the stage before the shield passes, the stage during the shield is passing through and the stage after the shield has passed. The first stage begins at where 15m ahead of the excavation surface, which accounts for 10% to 20% of the total settlement. The second stage begins when the shield reaches the excavation surface, which accounts for 50% of the total settlement. The third stage caused by the consolidation of soil begins at where 30m behind of excavation surface, which accounts for 30% to 40% of the total settlement.

(4) In this paper, the influence of three factors on surface subsidence, which is thickness of overlying soil, rock mass conditions of different sections and excavation time, are investigated respectively. The corresponding control measures are put forward according to various reasons why ground surface settlement happens.

KEY WORDS: shield method, ground surface settlement, data analysis, control measures

目录

摘要 I

Abstract II

第一章 绪论 1

1.1 选题背景及研究的目的与意义 1

1.1.1 选题背景 1

1.1.2 研究的目的与意义 3

1.2 国内外研究现状 3

1.2.1 经验法 3

1.2.2 模型试验法 8

1.2.3 解析法 9

1.2.4 数值模拟法 10

1.3 研究内容 11

第二章 土压平衡盾构法原理 12

2.1 盾构法基本介绍 12

2.1.1 盾构法适用范围 12

2.1.2 盾构法的优点与不足 12

2.1.3 盾构法的分类 13

2.2 土压平衡盾构的基本原理 13

2.2.1 土压平衡盾构机简介 13

2.2.2 土压平衡盾构开挖原理 14

2.2.3 土压平衡盾构的施工工序与技术要求 16

2.3 本章小结 16

第三章 盾构施工引起的地表沉降机理分析 18

3.1 地表变形的时空效应 18

3.1.1 地表变形的时间效应 18

3.1.2 地表变形的空间效应 18

3.2 地表沉降机理 19

3.2.1 地层损失 19

3.2.2 土体固结沉降 22

3.3 引起地表沉降的影响因素 24

3.4 本章小结 28

第四章 工程概况及监测方案设计 29

4.1 工程概况 29

4.1.1 工程简介 29

4.1.2 地质条件 30

4.1.3 水文条件 33

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