大型深基坑逆作开挖变形性状研究

发布时间：2018-07-28 15:55

【摘要】：在城市交通繁忙和紧邻高层建筑物的地段修建大型地下车站，如何减少对路面交通的影响，保护临近建筑物的安全，同时又保证工期，降低造价，采用明挖顺作和盖挖逆作相结合的修建方法，可以较好地解决上述工程难题。首先，本文对基坑工程的发展、逆作法的优缺点和适用范围、深基坑变形机理及国内外研究现状进行了介绍，在此基础上总结了基坑变形的影响因素。其次，以广深港客运专线福田站为工程背景，对其工程概况进行了简单介绍，包括车站的基本情况，工程地质、水文地质及气候特征，基坑分段与围护方案，基坑降水和开挖等。针对福田站工程结构复杂、规模大、工期紧，地质条件复杂，安全风险大等特点，提出了施工过程中重难点问题的应对措施。然后，以基坑变形性状为研究对象，运用MIDAS/GTS有限元软件建立逆作开挖段的三维模型，对开挖过程中地下连续墙深层水平位移、坑底土体隆起和坑外地表土体沉降等相关内容进行了较深入的研究，并通过改变围护结构参数和超载大小，分析了地下连续墙厚度、墙体嵌固深度、墙体弹性模量、地表超载和立柱桩桩径共计五个因素对基坑变形的影响，以期实现基坑围护结构设计优化。最后，福田站在基坑施工过程中，由第三方进行了全面、系统的监测，，建立了五级预警体系。将有限元数值模拟结果和实测数据进行分析比较，总结模拟计算得出的基坑变形与工程实际之间的差异并分析原因。本文的研究具有一定的实用价值，可为今后同类工程建设和研究工作提供借鉴参考。
[Abstract]:How to reduce the impact on road traffic, protect the safety of adjacent buildings, at the same time guarantee the construction period and reduce the cost of constructing large underground stations in the areas with heavy traffic and adjacent high-rise buildings, The construction method combining open excavation with cover excavation and reverse construction can solve the above problems well. Firstly, this paper introduces the development of foundation pit engineering, the advantages and disadvantages and application scope of the reverse method, the deformation mechanism of deep foundation pit and the research status at home and abroad, and summarizes the influencing factors of foundation pit deformation. Secondly, taking the Futian station of Guangzhou-Shenzhen passenger dedicated line as the engineering background, this paper briefly introduces the general situation of the project, including the basic conditions of the station, engineering geology, hydrogeology and climate characteristics, foundation pit segmentation and enclosure scheme. Foundation pit dewatering and excavation. In view of the complex structure, large scale, tight construction period, complex geological conditions and high safety risk of the Futian Station, the countermeasures of the heavy and difficult problems in the construction process are put forward. Then, taking the deformation behavior of foundation pit as the research object, using the MIDAS/GTS finite element software to establish the three-dimensional model of the inverse excavation section, the horizontal displacement of the underground continuous wall in the course of excavation is analyzed. By changing the parameters of enclosure structure and overloading, the thickness of underground continuous wall, the depth of embedded wall, the elastic modulus of wall are analyzed, which are related to the uplift of the bottom soil and the settlement of the surface soil in the pit, and by changing the parameters of the enclosure structure and the size of the overload, the thickness of the underground continuous wall is analyzed. In order to optimize the design of retaining structure of foundation pit, the influence of five factors, namely ground overload and pile diameter of vertical column, on the deformation of foundation pit is discussed in this paper. Finally, Futian station in the foundation pit construction process, by a third party to carry out a comprehensive, systematic monitoring, the establishment of a five-level early warning system. The finite element numerical simulation results are compared with the measured data, and the difference between the foundation pit deformation and the engineering practice is summarized and the reasons are analyzed. The research in this paper has certain practical value and can provide reference for similar engineering construction and research work in the future.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU753

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