坑中坑式基坑工程支护结构变形有限元分析

发布时间：2018-04-28 18:23

本文选题：坑中坑式基坑工程 + 基坑变形　；参考：《华南理工大学》2014年硕士论文

【摘要】：由于建筑物地下室功能的需要或地下室基础存在大大小小的承台,或者城市地下空间开发与地铁车站共建，导致基坑坑底深度不尽相同，于是就出现了二级及多级基坑这一比较特殊的情况——坑中坑。在坑中坑式基坑工程中，人们一般大多关心开挖至外坑坑底过程中基坑的稳定性和安全性，而往往忽略了基坑内部的坑中坑对整个外围基坑的影响。然而，，现有的规范规程并没有提及坑中坑的相关设计原则，相关的研究及文献也很少提及，所以坑中坑的开挖对于外坑变形的影响就很难考虑。本文针对广州市某一坑中坑式基坑工程实例，利用有限元分析软件MIDAS/GTS对其进行三维有限元模型的建立和分析，同时探讨了不同影响因素下坑中坑对外坑支护结构的影响，主要内容如下： 1、介绍了基坑工程相关的基本理论，包括水土压力的计算，基坑工程的失稳形式，基坑工程的变形形式及其时空效应，基坑工程的内力计算方法，基坑工程相关的有限元理论，以及岩土工程中土的三个本构模型：线弹性模型、非线性线弹性模型和弹塑性模型。 2、对简化模型进行数值模拟，分析不同影响因素如坑中坑深度、内外坑之间的距离、土体性质、坑中坑支护结构刚度以及坑中坑支护形式等对外坑支护结构的影响。通过分析得到的结论可以为工程实践提供指导意义。 3、对广州市某坑中坑式基坑工程运用MIDAS/GTS软件进行三维有限元模型的建立与分析，将计算结果与监测结果进行对比，以验证三维有限元模型的合理性和适用性。
[Abstract]:Due to the need of the basement function of the building or the existence of large and small caps in the basement foundation, or because of the development of underground space in the city and the co-construction of the subway station, the depth of the pit bottom is different. Therefore, the two-stage and multi-stage foundation pit is a special case-pit in the pit. In the pit pit engineering, people usually care about the stability and safety of the pit during the excavation to the bottom of the outer pit, but often ignore the influence of the pit inside the pit on the whole peripheral pit. However, the existing specifications do not mention the relevant design principles of the pit in the pit, and the relevant research and literature are also rarely mentioned, so it is difficult to consider the influence of the excavation of the pit in the pit on the deformation of the outer pit. In this paper, the three-dimensional finite element model of a pit in Guangzhou is established and analyzed by using the finite element analysis software MIDAS/GTS, and the influence of different factors on the supporting structure of the external pit is discussed. The main contents are as follows: 1. The basic theories of foundation pit engineering are introduced, including the calculation of soil and water pressure, the form of instability of foundation pit engineering, the deformation form of foundation pit engineering and its space-time effect, the calculation method of internal force of foundation pit engineering, and the finite element theory related to foundation pit engineering. And three constitutive models of soil in geotechnical engineering: linear elastic model, nonlinear linear elastic model and elastic-plastic model. 2. The simplified model is numerically simulated to analyze the influence of different factors, such as pit depth, distance between inside and outside pits, soil properties, stiffness of pit supporting structure and the form of pit support, etc. The conclusions obtained from the analysis can provide guidance for engineering practice. 3. In order to verify the rationality and applicability of the 3D finite element model, the three-dimensional finite element model is established and analyzed by using MIDAS/GTS software in a pit pit project in Guangzhou, and the calculated results are compared with the monitoring results in order to verify the rationality and applicability of the three-dimensional finite element model.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU753

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