深基坑施工与邻近群桩基础加载的相互影响研究

发布时间：2019-05-22 08:10

【摘要】：随着城市地下空间开发的不断深入,许多基坑出现在建筑物密集区,当深基坑工程附近存在建筑物桩基础同步施工或工序交错施工,尤其是在建建筑物离深基坑很近时,进行基坑设计既要考虑邻近建筑物桩基础加载对基坑的影响,又要考虑基坑开挖对邻近建筑物的影响,在此条件下,研究深基坑施工与邻近群桩基础加载的相互影响关系,具有一定的现实意义和实用价值。本文依托的成绵乐客运专线双流机场站深基坑开挖深度为20.2m,最大基坑开挖宽度为55.2m,其与邻近在建的T2航站楼斜拱群桩基础承台边净距仅14.8m,而且斜拱承台落拱时承台还受到高达12160kN的指向基坑的横向水平力。以此为工程背景,本文采用岩土有限元数值分析、解析分析和施工监测资料分析相结合的方法,对深基坑施工与邻近群桩基础加载的相互影响进行研究分析。本文的研究课题主要涵盖以下几个方面的内容：首先,采用岩土有限元软件对基坑开挖至不同深度进行群桩基础加载时基坑和群桩基础的应力场和位移场分别进行数值分析,在数值分析计算结果的基础上,分别对围护桩和群桩基础的水平位移、围护桩土压力以及围护桩和群桩基础弯矩进行分析,从而得到基坑开挖至不同深度进行群桩基础加载的各种计算条件下围护桩和群桩基础的变形和受力特点。然后,在上述研究的基础上,对基坑开挖至不同深度群桩基础加载的基坑和群桩基础的水平位移、围护桩土压力以及围护桩和群桩基础弯矩分别进行对比分析,进而研究不同开挖深度进行群桩基础加载时群桩基础加载对基坑围护桩身位移、弯矩和围护桩土压力的影响以及基坑开挖对邻近群桩基础位移及弯矩的影响。从而得到深基坑施工和邻近群桩基础加载的相互影响规律。最后,将数值计算结果与现场监测资料(主要包括围护桩水平位移、承台顶水平位移和围护桩身弯矩)进行对比分析,以验证采用数值分析方法进行分析和计算的合理性和可靠性。
[Abstract]:With the deepening of the development of urban underground space, many foundation pit appear in the dense building area, when there is synchronous construction of building pile foundation or staggered construction of working procedure near the deep foundation pit project, especially when the building is very close to the deep foundation pit. In the design of foundation pit, not only the influence of pile foundation loading on foundation pit of adjacent buildings should be considered, but also the influence of foundation pit excavation on adjacent buildings should be considered. under this condition, the interaction between deep foundation pit construction and loading of adjacent pile group foundation should be studied. It has certain practical significance and practical value. In this paper, the excavation depth of deep foundation pit of Shuangliu Airport Station of Chengmianle passenger dedicated Line is 20.2m, the maximum excavation width of foundation pit is 55.2 m, and the net distance between the foundation platform of oblique arch pile group and the adjacent T2 terminal is only 14.8m. Moreover, when the inclined arch cap falls, the cap is also subjected to the horizontal force pointing to the foundation pit as high as 12160kN. Taking this as the engineering background, this paper uses the method of geotechnical finite element numerical analysis, analytical analysis and construction monitoring data analysis to study and analyze the interaction between the construction of deep foundation pit and the loading of adjacent pile group foundation. The research topic of this paper mainly covers the following aspects: firstly, the stress field and displacement field of foundation pit and pile group foundation are analyzed by using geotechnical finite element software to carry on the stress field and displacement field of foundation pit and pile group foundation when the foundation pit is excavated to different depths. On the basis of numerical analysis and calculation results, the horizontal displacement of retaining pile and pile group foundation, earth pressure of retaining pile and bending moment of retaining pile and pile group foundation are analyzed respectively. Thus, the deformation and stress characteristics of retaining pile and pile group foundation under various calculation conditions from foundation pit excavation to different depth loading of pile group foundation are obtained. Then, on the basis of the above research, the horizontal displacement of foundation pit and pile group foundation loaded from foundation pit excavation to different depth pile group foundation, the earth pressure of retaining pile and the bending moment of retaining pile and pile group foundation are compared and analyzed respectively. Furthermore, the influence of pile group foundation loading on the displacement, bending moment and earth pressure of retaining pile in foundation pit and the influence of foundation pit excavation on displacement and bending moment of adjacent pile group foundation are studied. Thus, the interaction between the construction of deep foundation pit and the loading of adjacent pile group foundation is obtained. Finally, the numerical results are compared with the field monitoring data (including the horizontal displacement of retaining pile, the horizontal displacement of cap top and the bending moment of retaining pile body). To verify the rationality and reliability of numerical analysis and calculation.
【学位授予单位】：福州大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU753.3

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