摘 要

自20世纪90年代以来，由于用地的紧张，城市供需矛盾的加剧，人们开始变得重视地下发展，也变得越来越依赖地下的开发和建设，由此就产生了许多深基坑工程。

基坑开挖会引起周围土体的变形和位移，但如果基坑开挖尺寸过大，就会对邻近的桩基础造成巨大的破坏，从而会引起地上建筑物的破坏；此时，支撑体系会分担一部分基坑开挖造成的土体压力，从而可以减小地下连续墙的变形，所以建立支撑体系是非常必要的。分析如何使得基坑在开挖过程中，能够充分利用支撑体系分担土体压力，对于桩基础起到保护作用是非常有必要的。首先建立模型，并且通过在不同情况下的位移和内力总结出支撑体系对于桩基础的影响，最后得出基坑开挖引起的土体位移对邻近桩基础有明显影响的结论，会使邻近桩基础产生比较大的位移和变形，而加了支撑体系之后，会对这种形变有着明显的抑制作用，所以对于基坑开挖，加支撑体系是很有必要的。

本文的课题就是由此为背景，分析基坑及其支撑体系对邻近建筑桩基础的影响，通过建立模型、模型计算、分析位移和内力，最后得出结论；

（1）加水平支撑是有利于减小基坑开挖对邻近桩基础的影响的。会对基坑开挖引起的土压力产生明显的抑制作用。但是加水平支撑的数量要根据实际情况来考虑，选出最具性价比的方案。

（2）在基坑开挖深度一致的条件下，基坑的宽度越大，对周围桩基础造成的影响就越大，因此在开挖宽度较大的基坑时，需要多加水平支撑来减小其对桩基础的影响。

（3）在基坑的宽度与开挖深度一致的条件下，基坑距离桩基础越近影响就越大，因此当基坑距离桩基础很近时，需要多加水平支撑，以此来减小其对桩基础的影响。

关键词：有限元分析；基坑；支撑体系；桩基础；结构变形

Analysis of the influence of foundation pit and its supporting system on pile foundation of high-rise building

Abstract

Since the 1990s, due to the shortage of land and the aggravation of the contradiction between urban supply and demand, people begin to attach importance to underground development and become more and more dependent on underground development and construction, which has resulted in many deep foundation pit projects.

Foundation pit excavation will cause the deformation and displacement of surrounding soil, but if the excavation size is too large, it will cause great damage to the adjacent pile foundation, which will lead to the destruction of buildings on the ground. At this time, the support system will share part of the soil pressure caused by foundation pit excavation, so as to reduce the deformation of underground diaphragm wall. Therefore, it is very necessary to establish the support system. It is necessary to analyze how to make full use of the support system to share the soil pressure during the excavation of the foundation pit, so as to protect the pile foundation. First model, and through the displacement and internal force under the condition of different concluded that the support system for the influence of pile foundation, finally it is concluded that the soil displacement caused by excavation on adjacent pile foundation have obvious influence, can make the adjacent pile foundation to produce larger displacement and deformation, and added a support system, will has a obvious inhibitory effect on the deformation, so for the foundation pit excavation, supporting system is very necessary.

Based on this background, the subject of this paper analyzes the impact of foundation pit and its supporting system on pile foundation of adjacent buildings, and draws a conclusion through the establishment of model, model calculation, analysis of displacement and internal forces.

(1) adding horizontal support is conducive to reducing the impact of foundation pit excavation on adjacent pile foundation. It will obviously restrain the earth pressure caused by foundation pit excavation. However, the amount of horizontal support should be considered according to the actual situation to select the most cost-effective scheme.

(2) under the condition that the excavation depth is consistent, the larger the width of the foundation pit, the greater the impact on the surrounding pile foundation will be. Therefore, when excavating the foundation pit with a large width, more horizontal support is needed to reduce the impact on the pile foundation.

(3) under the condition that the width of the foundation pit is consistent with the excavation depth, the closer the foundation pit is to the pile foundation, the greater the impact will be. Therefore, when the foundation pit is very close to the pile foundation, more horizontal support is needed to reduce its impact on the pile foundation.

Key words: Finite element analysis; Foundation pit; Support system; Pile foundation; Structural deformation

目 录

1 绪论 1

1.1 研究背景 1

1.2 基坑开挖对高层建筑桩的影响研究现状 2

1.2.1 深基坑开挖对邻近高层建筑物影响分析 2

1.2.2 深基坑开挖对于临近建筑物的数值分析 2

1.3 地下隧道对建筑桩基础的影响研究现状 3

1.3.1 地下隧道对高层建筑桩基础的影响分析 3

1.3.2 地下隧道施工对高层建筑桩基础的影响模拟 4

1.3.3 隧道开挖模拟研究 5

1.4 基坑开挖风险研究 5

1.4.1 基坑开挖风险分析 5

1.4.2 基坑开挖风险数据模拟研究 7

2 支撑体系在不同参数下的影响分析 8

2.1 有限元程序简介 8

2.2 工程背景 8

2.2.1 工程概况 8

2.2.2 土层情况介绍 9

2.2.3 工程参数 9

2.2.4 建立几何模型 10

2.2.5 建模顺序 11

2.3 介绍整体模型 12

2.4 不同开挖深度对支撑体系影响分析 14

2.5 不同内支撑对支撑体系影响分析 15

2.5.1 开挖至-10m时不同内支撑分析 15

2.5.2 开挖至-15m时不同内支撑分析 20

2.5.3 不同锚杆对支撑体系影响分析 25

2.6 不同基坑宽度分析 28

2.6.1 基坑不同宽度情况下分析 28

2.6.2 基坑距离桩基础不同宽度分析 32