城市浅埋软弱围岩地铁隧道施工引起的地表沉降及控制研究

发布时间：2018-08-24 16:20

【摘要】：城市浅埋软弱围岩中暗挖大跨地铁隧道引起的地表沉降问题一直是地铁隧道建设者们尤为关注的话题，同时也是极难控制且亟待解决的关键性问题。在岩土体内部暗挖地铁隧道将不可避免地引起地层变形，当变形达到一定程度时，将对地面建（构）筑物及周边生态环境造成严重破坏，，甚至危及人民生命财产安全。因此，对隧道施工引起的地表沉降问题进行深入研究，探求不同开挖方法引起的沉降变化规律，提出切实有效的沉降控制措施，对地铁隧道的设计、施工和安全运营都具有十分重要的意义。论文主要分析重庆地铁1号线石歇区间隧道施工引起的地表沉降问题及数值模拟研究。首先，介绍了隧道开挖引起地层移动的主要理论。总结了城市浅埋软弱围岩中修建大跨地铁隧道引起的地层变形规律，并详细阐述了地表横向变形规律及纵向变形规律。其次，介绍了隧道开挖引起地表沉降的控制原理及对策，并阐述了沉降控制标准及沉降容许值的确定方法。对具体沉降控制措施及其控制效果进行了论述，得出了采用合理的控制措施可有效控制地表沉降的结论。再次，介绍了ANSYS软件在地下工程中的应用，D—P屈服准则及有限单元法的基本分析过程。简要介绍了依托工程水文地质情况，为合理的选取材料参数做准备，对依托工程采用了不同施工工法数值模拟及地层预加固法数值模拟，通过分析比较各个工法的沉降变化情况，得出了双侧壁导坑法为沉降控制的最佳施工工法的结论。对最佳施工工法采取加固措施后，结果表明，地层预加固法的应用可很好地减小地表沉降。最后，结合依托工程监测数据,分析了隧道施工引起的地层变形情况，沉降分析结果与数值模拟结果具有一致性，进一步验证了数值模拟分析结果的可靠性，同时也论证了重庆地铁1号线石歇区间隧道采用双侧壁导坑法和地层预加固法施工对地层沉降控制的合理性。
[Abstract]:The problem of surface settlement caused by underground excavation of large-span subway tunnel in shallow buried soft surrounding rock is always a topic of special concern for subway tunnel builders, and it is also a key problem to be solved urgently. Underground tunnel excavation in the body of rock and soil will inevitably cause formation deformation. When deformation reaches a certain degree, it will cause serious damage to ground building and surrounding ecological environment, and even endanger the safety of people's life and property. Therefore, the ground surface settlement caused by tunnel construction is deeply studied, the law of settlement change caused by different excavation methods is explored, and practical and effective settlement control measures are put forward to design the subway tunnel. Construction and safe operation are of great significance. The paper mainly analyzes the surface settlement problem and numerical simulation study caused by the tunnel construction in Shihe section of Chongqing Metro Line 1. Firstly, the main theory of stratum movement caused by tunnel excavation is introduced. This paper summarizes the law of formation deformation caused by the construction of large-span subway tunnel in the shallow buried soft surrounding rock of the city, and expounds in detail the law of transverse and longitudinal deformation of the ground surface. Secondly, the paper introduces the control principle and countermeasures of the ground subsidence caused by tunnel excavation, and expounds the settlement control standard and the method of determining the allowable settlement value. The concrete settlement control measures and their control effects are discussed, and the conclusion is drawn that reasonable control measures can effectively control the surface subsidence. Thirdly, the application of ANSYS software in underground engineering is introduced. This paper briefly introduces hydrogeological conditions of relying engineering, prepares for reasonable selection of material parameters, uses different construction methods numerical simulation and stratum pre-reinforcement numerical simulation for relying engineering. Based on the analysis and comparison of the settlement changes of each method, the conclusion is drawn that the double side wall guide pit method is the best construction method for settlement control. The results show that the application of the pre-reinforcement method can reduce the surface subsidence well. Finally, based on the monitoring data of engineering, the ground deformation caused by tunnel construction is analyzed. The result of settlement analysis is consistent with the result of numerical simulation, which further verifies the reliability of the result of numerical simulation. At the same time, it also proves the rationality of the construction of double-sidewall tunnel and pre-reinforcement method to control the formation settlement in the Shihe section tunnel of Chongqing Metro Line No. 1.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U455;U231.3

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