深基坑双排桩支护桩间土计算模型及受力机理研究

发布时间：2018-11-23 17:28

【摘要】：基坑双排桩支护结构体系具有侧向刚度大、抗倾覆能力强、施工方便、对周边环境影响较小等优点,比较适合于变形控制要求严格、土质条件较差的基坑工程中,是今后基坑工程中非常具有潜力的支护形式之一。然而,由于基坑双排桩支护结构体系的受力及变形机理非常复杂,其计算理论的研究还尚未成熟,从而严重阻碍了基坑双排桩支护体系的发展。本文从桩间土等效代换的问题出发,对基坑双排桩支护结构的计算方法,以及基坑双排桩支护结构的受力和变形特性做了进一步的研究工作,具体内容如下所示:(1)通过分析与总结现行国家和部分地方基坑行业规程中的双排桩计算方法,从桩间土水平等效结构体系的等效刚度入手,提出了三种基于规程的改进双排桩支护结构计算模型。(2)基于等效桁架模型,将四边形桩间土实体单元等效为六杆件桁架单元,进而提出基于等效桁架模型的改进基坑双排桩支护结构计算模型,并对该计算模型的使用做详细的说明。(3)基于矩阵位移法对所提出的改进计算模型进行求解。按平面杆系结构有限元法的思想,建立基坑双排桩支护结构的力学模型,利用矩阵位移法编写相应的MATLAB计算程序,从而实现对双排桩支护结构内力及变形的求解。然后,通过两个具体算例的对比分析,对所提出的四个双排桩改进计算模型的可行性及优缺点展开讨论。(4)将文中提出的基于等效桁架模型的改进双排桩计算模型应用到典型工程案例中,采用自编MATLAB计算程序包对该工程案例进行相关的计算。首先,采用自编MATLAB计算程序对该工程典型剖面的各个工况进行分析计算,进而探讨各个工况下双排桩支护结构内力及位移的变化规律。然后,利用该自编MATLAB计算程序,分析桩间土压缩模量变化对基坑双排桩支护结构受力及变形特性的影响。
[Abstract]:The double row pile supporting structure system of foundation pit has the advantages of large lateral stiffness, strong capsizing resistance, easy construction and less influence on the surrounding environment. It is suitable for foundation pit engineering with strict deformation control requirements and poor soil conditions. It is one of the support forms with great potential in foundation pit engineering in the future. However, due to the complexity of the mechanism of stress and deformation of the double-row pile supporting system of foundation pit, the research of its calculation theory is not yet mature, which seriously hinders the development of the double-row pile supporting system of foundation pit. Starting from the problem of equivalent replacement of soil between piles, this paper makes further research on the calculation method of double-row pile supporting structure of foundation pit, as well as the mechanical and deformation characteristics of double-row pile supporting structure of foundation pit. The concrete contents are as follows: (1) by analyzing and summarizing the calculation methods of double-row piles in the current national and local foundation pit industry regulations, starting with the equivalent stiffness of the horizontal equivalent structure system between piles, Based on the equivalent truss model, the soil solid element between the quadrilateral piles is equivalent to the six-bar truss element. Then an improved calculation model of double-row pile supporting structure based on equivalent truss model is proposed, and the use of the model is explained in detail. (3) the improved calculation model is solved based on the matrix displacement method. According to the idea of finite element method of plane bar system structure, the mechanical model of double-row pile supporting structure of foundation pit is established, and the corresponding MATLAB calculation program is compiled by using matrix displacement method, so as to realize the solution of internal force and deformation of double-row pile supporting structure. Then, through the comparative analysis of two concrete examples, The feasibility, advantages and disadvantages of the four improved calculation models for double-row piles are discussed. (4) the improved double-row pile calculation model based on equivalent truss model is applied to typical engineering cases. The relevant calculation of the project case is carried out by using the self-made MATLAB program package. Firstly, the internal force and displacement of double-row pile supporting structure are analyzed and calculated by using self-compiled MATLAB program to analyze and calculate the typical working conditions of the project, and then the variation law of internal force and displacement of double-row pile supporting structure under each working condition is discussed. Then, the influence of soil compression modulus variation between piles on the mechanical and deformation characteristics of double-row pile supporting structure of foundation pit is analyzed by using the self-compiled MATLAB program.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU473.1

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