香耳山小净距隧道洞口浅埋偏压段施工方案动态研究

发布时间：2018-04-14 08:46

本文选题：香耳山隧道 + 小净距　；参考：《西华大学》2015年硕士论文

【摘要】：在长期山岭高速公路隧道施工中,隧道洞口段施工往往是整个施工过程中的困难之处。作为隧道咽喉的洞口段,其最普遍的特征包括:多长期受到风化作用,围岩普遍存在较破碎情况,并且普遍夹杂土层;覆盖层通常比较薄,且覆盖层厚度一般不均匀,容易形成浅埋偏压段。所以在这种成拱效应很难发挥作用的情况下,如何因地制宜的确定施工方案与监控量测方案,如何确保安全,如何提高项目建设的经济效益,如何在满足一定工期要求前提下,减少对围岩的扰动,这些问题均急需解决。本文以香耳山小净距隧道洞口浅埋偏压段工程为依托,根据该隧道洞口工程的实际地形地貌、工程地质条件,参考洞口段现场进洞实际方案(选择三台阶七步开挖预留核心土法,深埋侧作为先行洞,浅埋侧作为后行洞,导洞开挖分台阶先右侧后左侧),提出三个新的进洞方案:同样选择三台阶七步开挖预留核心土法,但是变换先行洞和后行洞进洞顺序,以及导洞开挖顺序。通过现场监控量测技术与理论数值模拟研究技术相互对比,分析了香耳山小净距隧道洞口浅埋偏压段施工动态力学过程。根据进洞过程中围岩应变的变化规律、塑性区分布形态和发展规律、围岩应力特征、初期支护应力变化规律等方面,研究香耳山小净距隧道洞口浅埋偏压段不同进洞施工方案对洞口浅埋偏压段围岩稳定性的影响机制。通过对比分析,得出了选择三台阶七步开挖预留核心土法,深埋侧作为先行洞,浅埋侧作为后行洞,导洞开挖先右侧后左侧(不分台阶)的开挖方案,是香耳山小净距隧道洞口浅埋偏压段较优施工方案的结论。本文探讨成果可对香耳山小净距隧道洞口浅埋偏压段工程的施工提供一定指导和建议,并且对类似山岭隧道洞口浅埋偏压段施工方案的确定提供借鉴和参考作用,对确保安全施工和科学指导类似隧道洞口工程施工具有一定的意义。
[Abstract]:In the long-term tunnel construction of mountain highway, the construction of tunnel entrance section is often the difficulty in the whole construction process.As the orifice of the tunnel throat, the most common characteristics of the section include: long term weathering, the surrounding rock is generally broken, and generally mixed soil layer, the overburden is usually thin, and the thickness of the overburden is generally uneven.It is easy to form shallow buried bias section.So how to determine the construction plan and the monitoring and measuring scheme, how to ensure the safety, how to improve the economic benefit of the project construction, how to meet the requirements of the construction period under the condition that it is difficult to play the role of the arch effect, and how to determine the construction plan and the monitoring and measuring scheme according to the local conditions.To reduce the disturbance of surrounding rock, these problems need to be solved urgently.In this paper, based on the shallow burying partial pressure section of the small distance tunnel entrance of Xiangershan tunnel, according to the actual topography and geomorphology and the engineering geological conditions of the tunnel entrance project,Referring to the actual scheme of hole entry in the section of Dongkou (selecting three steps and seven steps to excavate the reserved core soil method, the deep buried side is used as the first tunnel, the shallow side as the rear tunnel, and the shallow side as the rear tunnel).In this paper, three new excavation schemes are put forward: selecting three steps and seven steps of excavation to reserve the core soil, but changing the order of advance and backward holes, as well as the excavation sequence of guide holes.Based on the comparison of field monitoring and measurement technology and theoretical numerical simulation technology, the dynamic mechanical process of shallow burying bias section of Xiangershan small distance tunnel is analyzed.According to the variation law of surrounding rock strain, the distribution and development law of plastic zone, the stress characteristics of surrounding rock, the variation law of initial support stress, etc.This paper studies the influence mechanism of different tunnel entry schemes on the stability of surrounding rock of shallow buried eccentric section of Xiangershan small distance tunnel.Through comparison and analysis, the excavation scheme of selecting three steps and seven steps to excavate the core soil method, the deep buried side as the first tunnel, the shallow side as the rear tunnel, the guide tunnel excavation first on the right side and then on the left side (without steps) is obtained.It is the conclusion of the optimal construction scheme for the shallow buried bias section at the entrance of the small clear distance tunnel in Xiangershan.The results of this paper can provide some guidance and suggestions for the construction of shallow burying partial pressure section at the entrance of Xiangershan small distance tunnel, and provide reference and reference for the determination of the construction scheme of shallow buried bias section at the entrance of similar mountain tunnel.It has certain significance for ensuring safety construction and guiding similar tunnel entrance construction scientifically.
【学位授予单位】：西华大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U455.4

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