铁路隧道底部上拱病害机理分析及整治技术研究

发布时间：2018-07-26 17:20

【摘要】：随着我国铁路的迅猛发展,铁路隧道的建设规模和数量也日益增多。由于隧道所处地质环境复杂多变,底部结构上拱现象时有发生,严重影响了铁路运营和工程建设的安全,因此,开展对铁路隧道底部上拱机理及整治技术的研究具有重要的理论意义和工程实用价值。本文针对铁路隧道底部结构上拱病害,围绕隧底上拱机理及整治技术,通过现场调查、理论分析以及数值模拟,统计分析了产生隧底上拱的主要影响因素、原因及机理,研究了不同影响因素对隧道底部结构变形和受力的影响,提出了隧底上拱病害的整治措施。主要研究内容如下:(1)统计分析了产生隧底上拱的主要影响因素、原因及机理。通过调查全路10条线共18座隧道底部结构上拱病害情况,统计了隧底上拱的主要影响因素,依次为地下水、施工质量、膨胀岩、结构匹配性及地应力,分析了隧底发生上拱的渐进性演变规律,隧底上拱与时间密切相关,在底部围岩出现一定范围劣损破坏后产生。(2)研究了不同影响因素对隧道底部结构变形和受力的影响。通过有限元软件模拟了隧道发生上拱时底部结构变形和受力分布特征,仰拱填充层顶面基本表现为受拉,且中心水沟及其两侧填充层顶面中部位置主拉应力较大,并由顶面向结构内部减小。分析了底部结构变形和受力随不同影响因素的变化趋势,明确了各因素对底部结构变形和受力的影响程度,由大到小依次为膨胀力、仰拱矢跨比、仰拱厚度、围岩劣化程度。(3)提出了铁路隧道底部上拱病害的整治措施,明确了技术特点、适用范围以及关键参数。锚注一体化通过锚杆和浆料的共同作用,提高了底部围岩完整性并隔绝了地下水;“轻型井点降水+注浆”降低了地下水位,提高了底部围岩的承载力;隧道换底技术通过拆除既有基底结构并强化设计,提高了结构抗力;基底换填通过置换不良地层,提高了底部围岩抵抗变形的能力。(4)以狮子岭隧道底部上拱病害为例,结合隧道自身结构特点,提出了下沉式纵横梁长距离架空线路换底整治措施,隧道采用的纵梁悬挂横梁方案施工便利且纵横梁体系稳定可靠,实现了有限天窗时间内长距离开挖段线路的全部架空,多个开挖段同步快速换底施工,保证了运营安全,取得了良好的工程效果。
[Abstract]:With the rapid development of railway in China, the construction scale and quantity of railway tunnel are increasing day by day. Because the geological environment in which the tunnel is located is complex and changeable, the phenomenon of arch on the bottom structure occurs from time to time, which seriously affects the safety of railway operation and engineering construction. It is of great theoretical significance and practical value to study the mechanism of the upper arch at the bottom of the railway tunnel and the remediation technology. Aiming at the disease of the upper arch in the bottom structure of railway tunnel, the paper analyzes the main influencing factors, causes and mechanism of the arch on the bottom of the tunnel by field investigation, theoretical analysis and numerical simulation. The influence of different factors on the deformation and stress of the tunnel bottom structure is studied, and the treatment measures of the tunnel bottom arch disease are put forward. The main contents are as follows: (1) the main influencing factors, causes and mechanism of the tunnel bottom arch are analyzed statistically. Through the investigation of the disease of the arch on the bottom structure of 18 tunnels on 10 lines of the whole road, the main influencing factors of the arch at the bottom of the tunnel are analyzed, including groundwater, construction quality, expansive rock, structural matching and in-situ stress, in order of ground water, construction quality, expansive rock, structure matching and in-situ stress. The progressive evolution law of the upper arch in the bottom of the tunnel is analyzed. The arch of the bottom is closely related to time and occurs after a certain range of bad damage occurs in the surrounding rock at the bottom. (2) the influence of different factors on the deformation and force of the structure at the bottom of the tunnel is studied. The deformation and stress distribution characteristics of the bottom structure of the tunnel are simulated by finite element software. The top surface of the inverted arch filled layer is basically under tension, and the main tensile stress is larger in the central ditch and the middle part of the top surface of the filling layer on both sides. And the interior of the structure is reduced by the top-facing structure. The variation trend of deformation and force of bottom structure with different influencing factors is analyzed, and the degree of influence of each factor on deformation and force of bottom structure is clarified. The order from large to small is expansion force, rise-span ratio of inverted arch, thickness of inverted arch. (3) the treatment measures of the bottom arch disease of railway tunnel are put forward, and the technical characteristics, applicable range and key parameters are defined. The integration of anchor and grouting improves the integrity of the surrounding rock at the bottom and insulates the groundwater through the joint action of the anchor rod and the slurry, and reduces the groundwater level and increases the bearing capacity of the surrounding rock at the bottom by "light well point dewatering grouting". By removing the existing base structure and strengthening the design, the tunnel bottom changing technology improves the resistance of the structure, and the base replacement improves the ability of the bottom wall rock to resist the deformation by replacing the bad stratum. (4) taking the disease of the upper arch at the bottom of the Shihiling tunnel as an example, Combined with the structural characteristics of the tunnel itself, this paper puts forward the bottom changing measures for the long distance overhead lines of the submerged longitudinal and horizontal beams. The longitudinal beam suspension beam scheme adopted in the tunnel is convenient in construction and the system of the longitudinal and horizontal beams is stable and reliable. All the lines of the long distance excavation section in the finite skylight time are set up, and several excavation sections are constructed synchronously and quickly, which ensures the safety of operation and achieves good engineering effect.
【学位授予单位】：中国铁道科学研究院
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U457.2

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