论文标题:浅埋暗挖大跨度地铁隧道地表沉降分析
Study on the Ground Surface Settlement of Large-span Metro Tunnel with Shallow-buried Tunneling Method
论文作者
论文导师 张子新,论文学位 硕士,论文专业 桥梁与隧道工程
论文单位 同济大学,点击次数 21,论文页数 91页File Size9180K
2007-03-01论文免费下载 http://paper.dic123.com/lunwen_106430847/
metro tunnel;; shallow-buried tunneling method;; large-span;; field monitoring;; excavation simulation;; finite element method;; ground surface settlement;; settlement trough
城市暗挖法地铁隧道施工引起的地表沉降问题是地铁隧道建设中人们尤为关注的问题，同时也是最难控制且亟待解决的关键性问题之一。地表沉降被普遍认为是由于地层损失引起的，暗挖法地铁隧道施工是在岩土体内部进行的，隧道施工将不可避免地扰动地下岩土体，破坏原有的平衡状态，引起地层变形。变形达到一定程度时，将会对地面建筑物和生态环境造成破坏，甚至会危及人民财产及生命安全。因此，对隧道施工过程中的地表沉降进行深入研究，探求不同区域、不同地层中地表沉降变化的基本特性和规律，论证地层变形的机理，进而提出合理可靠的预测方法和控制措施，对地铁隧道的设计、施工和安全运营有十分重要的意义。本文主要围绕广州地铁二号线公园前站至纪念堂站区间软弱围岩浅埋暗挖大跨度地铁隧道工程中的地表沉降变化规律进行分析和数值模拟研究。 首先，针对地层松软的埋深浅大跨度地铁隧道，提出了合理的施工顺序和步骤，并应用于工程实践，取得了较好的成果，而且，对类似工程有较好的指导意义。 其次，分析了隧道开挖过程的有限元基本理论以及岩土体动态施工力学理论。并对提出的合理隧道施工顺序和步骤进行平面有限元数值模拟，论证了本文施工顺序和方法在本工程实践中的有效性和适用性。 最后，将数值模拟结果与现场监控量测得到的数据进行对比分析，有力地验证了本文提出的施工顺序的合理性，以及数值模拟方法的正确性及适用性。并且论证了采用合理的施工方法可以减小地表沉降。
Ground surface settlement of large-span metro tunnel by using shallow-buriedtunneling method is one of the worldwide concerned and most difficult controllingkey problems in the design of tunnel constrution in cities, and it is urgent to be solveddue to the need of constructions of large-span metro tunnel. Ground surfacesettlement is usually thought to be caused by volume losses of the stratum. Tunnelexcavation under the ground surface will inevitably disturb the surrounding soil mass,then, the state of equilibrium is broken, and the deformation is caused. When thedeformation is large, the upper buildings and ecological environment will bedestroied, even the lives and properties of human beings will be endangered.However, up to now, the settlement prediction and disposal measures, of largedeformation are still problems. Further study on the characteristics and variations ofground surface settlement of metro tunnel as well as mechanism of deformationshould be carried out, then reasonable settlement pridiction and effectiveprecautionary and disposal measures should be advanced, which are very significantto the design, construction and operation of metro tunnel. In this thesis, theoreticalanalysis and numerical simulation are performed to study the variations and themechanism of settlement at the ground surface with the background of line 2 ofmetros in Guangzhou City. First, reasonable construction sequences and steps are proposed according to theshallow-buried large-span metro tunnel in soft soil in Guangzhou, then they are putinto practice, and the results is acceptable. Moreover, the suggested excavationsequences and steps are a construction guide of similar tunnels. Second, finite element method of plane srtain is used to simulate theconstruction steps and processes of the metro tunnel, and the ultimate settlements atthe ground surface in different construction steps are smaller than those suggested instate codes. Therefore, the proposed excavation sequences and method are effectiveand applicable in the construction of line 2 of metro tunnels in Guangzhou. Finally, comparison of results from numerical simulation and data from fieldmonitoring show that the suggested excavation method is reasonable, and thefeasibility and applicability of the method of numerical simulation advised in thisthesis is also verified. In addition, the ground surface settlement of metro tunnel couldbe reduced by using proper job practice.
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