【作者】 陈莹；

【导师】 林从谋；

【作者基本信息】 华侨大学 ， 材建筑与土木工程， 2012， 硕士

【摘要】 目前，在我国所有公路隧道中断面面积在150m2以上的特大扁平断面隧道还相当少见。由于断面超大，扁平率增加，围岩形成塌落拱所需的埋深增大，洞口段一般存在浅埋偏压段，隧道对偏压问题敏感，施工不慎将导致塌方、冒顶等事故。本论文以国内少见的特大断面隧道——福泉高速扩建工程前鸥隧道为工程背景，结合现场试验和静力有限元分析等研究方法，对具有浅埋偏压特征的前欧隧道洞口段双侧壁导坑施工时围岩的稳定性进行深入研究，得到的主要研究成果与结论如下：１采用有限元软件ANSYS10.0建立特大断面隧道在双侧壁导坑法下的二维弹塑性模型，研究围岩及支护结构的受力和变形规律，进而得出特大断面浅埋偏压土质软岩隧道的划分界线。２综合考虑前鸥隧道本身特大断面浅埋偏压的特征，结合隧道洞口段的现场情况制定相应的试验方案，并获得相应的监控量测资料。通过整理分析监控量测资料，研究地表沉降及洞壁周边围岩位移规律。３基于前鸥隧道的现场情况，采用土质软岩参数建立相应的三维弹塑性模型，并验证模型的可靠性。同时分析围岩、衬砌、临时支撑和锚杆的力学响应和位移变形规律、围岩安全系数及应力影响半径，进而评价围岩的稳定性及支护结构的安全性，对保证隧道安全施工提供理论依据。4通过对比分析V级围岩和土质软岩下围岩及支护结构的应力变形情况，研究两者稳定性的差异。更多还原

【Abstract】 At present，super-large cross-section flat tunnels that cross-sectional area ismore than150square meters are still quite rare among all Chinese road tunnels. Sincethe cross-section is super large，compared with usual tunnels, the flat rate is muchhigher，and the sensitivity of tunnel on the issue of bias is increasing as well，Thisthesis will further study on surrounding rock’s stability around entrance ofsuper-large cross-section shallow-buried bias tunnel excavated by two-side pilotdrifting method，on the background of domestic rare large-span and super-largesection tunnel---FuQuan Highway extension project QianOu Tunnel and based on theresearch methods that Combining in-situ test with static finite element analysis. Someresearch fruits and conclusions are obtained as follows:1.Using two-dimensional elastoplasticity finite-element analysis with softwareANSYS10.0, to study transformation rules and stress of super-large cross-sectiontunnels’ surrounding rocks and supporting structures, which are constructed by twoside-wall pilot tunnel method to get demarcation of shallow and unsymmetricalsuper-large cross-section tunnels.2.To make a test scheme accordingly with thoughtful consideration of QianOutunnel’s characteristic that is shallow and unsymmetrical, super-large cross-sectionalas well as the site condition of tunnel portal. Some initial results of the research havebeen obtained through monitoring measurement test on the process of tunnelexcavation. Researching into those data, the general law of surface settlement anddeformation of surrounding rock was obtained.3.According to the actual situation of QianOu tunnel, a three-dimensionalnumerical model was established, and the applicability of this model was verified bycrossing experimental data，via this model the excavation process of the tunnel wassimulated. By analyzing the safety factor of surrounding rock and stress radius ofinfluence as well as strength response and displacement rules of surrounding rock,lining, falsework and bolt to evaluate the stability of surrounding rock and the safetyof supporting structures. And the evaluation give theory basis to safety and success ofthe tunnel construction. 4.Through comparing and analyzing class-V surrounding rock and surroundingrock under soil soft rock as well as the stress deformation of supporting structure, astudy is made on the differences of their stability.更多还原