近桥桩地铁隧道施工力学行为研究

发布时间：2018-11-11 10:21

【摘要】：随着我国经济社会的不断发展，城市人口迅速膨胀，交通拥堵问题已成为制约城市发展的瓶颈，修建地铁是解决该问题的重要途径。然而由于受到地下空间及线路走向的制约，线路将不可避免的穿越软弱地层及市政桥梁，在采用浅埋暗挖法施工时很容易对地层造成扰动，改变地层应力场和位移场的分布，引起地表沉降，桩基发生位移，隧道结构产生变形或破坏，尤其是不合理的施工方法和支护措施，将给工程带来巨大安全风险和经济损失，因此研究不同的施工方法和支护措施对地表下沉、隧道结构及邻近桩基变形的影响具有重要的现实意义。为分析不同施工方法及支护措施的影响，，文中依据一定的判别标准，采用理论分析与数值计算的方法对其进行了研究，以下为论文的主要内容和研究成果： (1)本文归纳了国内外浅埋暗挖隧道对地层变形、邻近桩基影响的现状，并总结了注浆加固在软弱地层中应用的案例，然后从隧道施工力学的角度探讨了地层变形、桩基移位的基本原理，最后从隧道施工技术的角度研究了隧道施工和注浆加固的方法，并依据规范、文献及工程经验制定了地表沉降、围岩失稳、结构破坏、桩基变形的判别标准。 (2)结合兰州地铁一号线焦家湾～东岗区间隧道穿越鱼儿沟桥工程，运用大型有限元软件ANSYS建立三维计算模型，计算分析台阶法、预留核心土法、CRD法对地表沉降、围岩塑性变形、衬砌结构变形和内力、桩基变位的影响规律，最后利用之前建立的判据分析各工法的优劣，从而选择合理的工法。 (3)在选定工法的基础上分析讨论不同开挖进尺对地表沉降、围岩塑性变形、衬砌结构变形和内力、桩基变位的影响规律，通过一定的判别标准，比较不同开挖进尺的施工安全性，从而选择合理的开挖进尺。 (4)在施工工法及开挖进尺一定的情况下，计算分析隧道拱部不同注浆范围对地表沉降、围岩塑性变形、衬砌结构变形和内力、桩基变位的影响规律，利用文中建立的判据比较分析不同注浆范围的施工安全性、经济性，从而选择合理的注浆范围。
[Abstract]:With the development of our country's economy and society, the urban population is expanding rapidly. Traffic congestion has become the bottleneck of the urban development. The construction of subway is an important way to solve this problem. However, due to the restriction of underground space and route direction, the line will inevitably cross the soft stratum and municipal bridge. It is easy to disturb the formation and change the distribution of stress field and displacement field when using shallow underground excavation method. Ground subsidence, displacement of pile foundation, deformation or destruction of tunnel structure, especially unreasonable construction methods and supporting measures, will bring huge safety risk and economic loss to the project. Therefore, it is of great practical significance to study the influence of different construction methods and supporting measures on the deformation of surface subsidence, tunnel structure and adjacent pile foundation. In order to analyze the influence of different construction methods and supporting measures, the theoretical analysis and numerical calculation methods are used to study them according to certain discriminant standards. The following are the main contents and achievements of the thesis: (1) this paper summarizes the present situation of the influence of shallow tunneling on formation deformation and adjacent pile foundation at home and abroad, and summarizes the case of grouting reinforcement in soft stratum. Then from the angle of tunnel construction mechanics, the basic principles of stratum deformation and pile foundation displacement are discussed. Finally, the methods of tunnel construction and grouting reinforcement are studied from the point of view of tunnel construction technology, and according to the specifications, The criteria of ground subsidence, rock instability, structural damage and pile foundation deformation have been established by literature and engineering experience. (2) combined with the project of crossing Yuergou Bridge of Jiaojiawan-Donggang Tunnel of Lanzhou Metro Line 1, the three-dimensional calculation model is established by using large-scale finite element software ANSYS, and the surface settlement is calculated and analyzed by step method, reserved core soil method and CRD method. The influence law of surrounding rock plastic deformation, lining structure deformation and internal force, pile foundation displacement is analyzed. Finally, the advantages and disadvantages of each construction method are analyzed by using the criteria established before, and the reasonable construction method is selected. (3) on the basis of the selected engineering method, the influence of different excavations on surface subsidence, plastic deformation of surrounding rock, deformation of lining structure and internal force, displacement of pile foundation is analyzed and discussed. Compare the construction safety of different excavation advance, and select reasonable excavation advance. (4) under the condition of certain construction method and excavation advance, the influence of different grouting range of tunnel arch on surface settlement, plastic deformation of surrounding rock, deformation of lining structure and internal force, displacement of pile foundation is calculated and analyzed. By comparing and analyzing the construction safety and economy of different grouting range, the reasonable grouting range is selected by using the criteria established in this paper.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U455.4;U231.3

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