浅埋偏压连拱隧道管棚作用机理与支护参数优化研究

发布时间：2018-05-07 06:48

本文选题：连拱隧道 + 管棚超前支护　；参考：《重庆交通大学》2016年硕士论文

【摘要】：管棚法作为浅埋暗挖工法的一种,为降低对地面活动及其他地下设施与管线的影响,近来已在地下隧道工程中得到广泛应用。管棚是为隧道施工所采用的一种辅助工法,主要为隧道开挖时提供临时挡土设施,同时减少施工时对地面活动及其他地下设施与管线的影响。特别在隧道施工处覆土厚度较小但无法以明挖覆盖方式施工的工程,管棚工法则具有其他工法所无法代替的优势。本文旨在熟悉管棚工法的施工特点基础上,综合利用理论解析法、数值分析法进行系统研究,并结合现场实测数据对本项工程的地表变形进行了全面系统对比分析,得出了以下一些见解:(1)在对隧道工作面上覆地层结构进行理论上的探讨前提下,总结了预加固结构对地层起到的促稳效应、梁拱效应、拉杆效应,揭示了其内在作用机理;归纳了隧道围岩压力的计算方法,在此基础上确定了浅埋偏压隧道管棚的受力荷载,并根据文克尔提出的土介质理想化理论建立管棚超前支护结构力学模型;以东山隧道为依托工程,对比分析了两种类型下管棚的力学响应结果,得出类型1状态下的管棚促稳作用优于类型2。(2)运用有限元软件midas gts nx对东山连拱隧道进行仿真模拟分析,讨论了隧道施工状态下管棚、围岩及中墙结构的变形规律及力学响应,模拟结果能基本反映出管棚预支护对地表变形的影响,实际施工前进行必要的数值分析可掌握土体的应力分布及位移沉降情况;对比分析了有、无管棚预支护情况下的隧道地表沉降、拱顶下沉,并通过现场实测数据验证其可靠性,分析表明管棚预支护体系在控制地表沉降和拱顶下沉方面取得良好的成效;探讨了掌子面稳定性问题及管棚预支护下的隧道掌子面围岩纵向位移变形趋势,得出管棚预加固区能有效抑制围岩破坏区域向地表延伸。(3)应用Matlab编程程序和midas gts nx数值分析软件,对影响隧道管棚预支护效果的管棚长度、管径大小、间排距、开挖进尺、布置形式等因素进行了不同工况下探讨,量化分析了各参数与超前支护效能发挥之间的关系,并提供了相应的参考值;综合工程实际给出了一套符合浅埋暗挖隧道管棚预加固参数设计方法。
[Abstract]:As a kind of shallow underground excavation method, pipe shed method has been widely used in underground tunnel engineering recently in order to reduce the influence on ground movement and other underground facilities and pipelines. Pipe shed is a kind of auxiliary construction method used for tunnel construction, which mainly provides temporary earth-retaining facilities for tunnel excavation and reduces the influence of construction on ground activity and other underground facilities and pipelines. Especially in the tunnel construction where the thickness of the overburden is small but can not be constructed by open excavation and cover, the pipe-shed method has the advantages that can not be replaced by other engineering methods. On the basis of familiar with the construction characteristics of the pipe-shed method, this paper makes a systematic study by comprehensive use of the theoretical analytical method and the numerical analysis method, and makes a comprehensive and systematic comparative analysis of the surface deformation of the project by combining with the field measured data. The following opinions are obtained: 1) on the premise of theoretical discussion on the overlying stratum structure of the tunnel face, the paper summarizes the effect of the prestrengthened structure on the stability of the stratum, the beam arch effect and the pull rod effect, and reveals its internal action mechanism. The calculation method of surrounding rock pressure of tunnel is summarized, and on this basis, the load of tunnel pipe shed under shallow partial pressure is determined, and the mechanical model of advance support structure of pipe shed is established according to the idealized theory of soil medium put forward by Winkle. Based on the engineering of Dongshan Tunnel, the mechanical responses of two types of pipe shed are compared and analyzed. It is concluded that the stability promotion effect of pipe shed under type 1 is better than that of type 2. 2) the simulation analysis of Dongshan multi-arch tunnel is carried out by using finite element software midas gts nx. The deformation law and mechanical response of pipe shed, surrounding rock and middle wall structure in tunnel construction are discussed. The simulation results can basically reflect the influence of pipe shed pre-support on surface deformation. The stress distribution and displacement settlement of soil can be grasped by necessary numerical analysis before actual construction, and the tunnel surface settlement and vault subsidence under the condition of pre-support without pipe shed are compared and analyzed, and its reliability is verified by the field measured data. The analysis shows that the pipe-shed pre-support system has achieved good results in controlling the surface subsidence and dome subsidence, and discusses the stability of the face of the tunnel and the trend of the longitudinal displacement and deformation of the surrounding rock of the tunnel face under the pre-support of the pipe shed. It is concluded that the prereinforcement zone of pipe shed can effectively restrain the extension of surrounding rock damage area to the surface. (3) by using Matlab program and midas gts nx numerical analysis software, the length, diameter, spacing and excavation advance of pipe shed, which affect the effect of pre-support of tunnel pipe shed, are studied. The layout form and other factors are discussed under different working conditions, and the relationship between each parameter and advance support efficiency is analyzed quantitatively, and the corresponding reference value is provided. A set of parameters design method for pre-reinforcement of pipe shed in shallow-buried tunnel is given.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U455.7

【相似文献】