深基坑桩锚支护优化研究及数值模拟

发布时间：2018-01-27 11:38

本文关键词： 深基坑工程桩锚支护扩体锚索 FLAC3D 数值分析　出处：《长安大学》2014年硕士论文　论文类型：学位论文

【摘要】：随着城市化步伐节奏加快，城市用地越来越紧张，各类高层建筑及地下工程大量兴建，导致深大基坑开挖不断增多，势必会对周围的建（构）物、地下管线及市政设施产生影响。为了减小基坑开挖对周边环境的影响，必须对基坑进行支护。假若基坑周围建（构）筑物要求高、场地地质条件复杂，，则控制基坑的变形和稳定变得尤为重要。本文以济南滨河商务中心深基坑项目为工程背景，以基坑支护结构安全等级对基坑稳定和变形的要求为基准，结合基坑周边环境和地质水文条件，选取桩锚支护作为基坑支护类型。基于地质条件、水文条件、周边环境及施工条件，选取扩大头锚索作为预应力锚索支护。通过设计文件、理论分析及数值模拟以三种工况对基坑支护进行研究，分析了三种工况对土体位移、桩身弯矩、锚索内力等方面的影响，确定了桩锚支护的优化模型，即桩与扩体锚索（囊式扩大头锚索）联合支护。主要研究内容如下： 1、从基本理论出发，对桩锚支护体系的构成、工作原理、计算方法及变形特性进行分析，重点分析了扩体锚索（囊式扩大头锚索）的基本构成、工作原理、计算方法以及适用条件。 2、以济南滨河商务中心深基坑工程为依托，运用FLAC3D有限差分软件，建立基坑三维数值模型，模拟了整个基坑开挖过程。 3、运用FLAC3D软件，分别模拟桩支护、桩与非扩体锚索联合支护、桩与扩体锚索联合支护这三种工况，深入分析各工况对土体位移、桩身弯矩以及锚索承载力的影响。最后，综合各工况对基坑支护变形和稳定的要求，确定最优支护类型，即桩与非扩体锚索（囊式扩体锚索）支护。
[Abstract]:With the acceleration of the pace of urbanization, urban land is becoming more and more tense, a large number of high-rise buildings and underground projects have been built, resulting in the increasing excavation of deep foundation pit, which is bound to be around the construction (structure). In order to reduce the influence of excavation on the surrounding environment, it is necessary to support the foundation pit. If the construction (construction) of the foundation pit is high, the geological conditions of the site are complex. It is very important to control the deformation and stability of foundation pit. This paper takes the deep foundation pit project of Jinan River Commercial Center as the engineering background, taking the requirement of foundation pit stability and deformation for the safety grade of foundation pit support structure as the benchmark, combining with the surrounding environment and geological and hydrological conditions of the foundation pit. Based on the geological conditions, hydrological conditions, surrounding environment and construction conditions, the enlarged head anchor cable is selected as the prestressed anchor cable support. Theoretical analysis and numerical simulation are used to study the foundation pit support under three conditions. The effects of three conditions on soil displacement, pile bending moment, internal force of anchor cable are analyzed, and the optimization model of pile and anchor support is determined. The main contents of the research are as follows: 1. Based on the basic theory, the structure, working principle, calculation method and deformation characteristic of pile anchor support system are analyzed, and the basic composition and working principle of expanded body anchor cable (saccade head anchor cable) are analyzed emphatically. Calculation method and applicable conditions. 2. Based on the deep foundation pit project of Jinan Binhe Commercial Center, the three-dimensional numerical model of foundation pit is established by using FLAC3D software, and the whole excavation process is simulated. 3, using FLAC3D software, respectively simulate the pile support, pile and non-expanded anchor cable combined support, pile and expanded anchor cable combined support, in-depth analysis of the displacement of soil under different conditions. The influence of pile bending moment and anchor cable bearing capacity. Finally, according to the requirements of foundation pit support deformation and stability, the optimal support type is determined, that is, pile and non-expanded anchor cable (capsule expanded anchor cable) support.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU753

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