复杂环境条件下大断面客专隧道下穿施工关键技术研究

发布时间：2018-06-28 05:30

本文选题：山岭隧道 + 下穿施工　；参考：《西安建筑科技大学》2017年硕士论文

【摘要】：论文以新建商丘至合肥至杭州铁路(安徽段)站前工程新大力寺隧道为工程背景,采用有限元数值模拟、现场监测和理论分析相结合的方法对复杂环境条件下大断面客专隧道下穿施工关键技术进行了分析研究,确定了山岭地区隧道下穿省道区域应采用的合理的施工工法,改进了爆破开挖设计方案,分析了隧道下穿新大力寺水库施工稳定性及水库对隧道后期运营的影响。论文主要完成的工作及取得的成果如下:(1)针对浅埋暗挖隧道穿越既有省道的施工工法问题,以新大力寺隧道下穿208省道段为工程实例,利用MIDAS GTS/NX软件进行有限元模拟分析,分别研究了二台阶法、三台阶法、六步CD法、双侧壁导坑法四种施工工法引起的隧道围岩及支护结构的受力和变形特性,基于数值模拟分析结果并结合不同工法的特点,推荐了大断面客专隧道下穿既有省道“大管棚护顶条件+六步CD法”施工方案,指导了该段的施工,跟踪施工进行的现场监测验证了推荐方案的合理、可行性。(2)对大断面客专隧道下穿省道施工时通行车辆荷载对施工隧道稳定性的影响,数值分析表明,就隧道周边位移分析而言,汽车运行对围岩位移无明显的影响;就围岩和衬砌的受力分析而言,路基下方与隧道轴线相交处隧道围岩及支护结构的应力有变化,但变化量较小。为保证隧道的稳定性,建议施工过程中应对道路宽度范围内的隧道洞内围岩进行加固处置,以确保施工安全。(3)讨论后期省道运营给新建隧道造成的振动影响,以保证运营过程中既有省道和新建隧道不相互影响,为今后类似山岭地区隧道下穿公路或铁路项目提供参考依据。(4)针对暗挖隧道钻爆法开挖对临近古建筑物的振动影响,以新大力寺隧道下穿新大力寺段为工程实例,分析了爆破时新大力寺隧道最危险点产生的振速和加速度情况,优化了施工爆破方案,并对两次优化施工爆破方案进行对比分析,最后确定了合理、可行的施工爆破方案,指导了隧道的爆破施工。(5)针对水库水的渗流对浅埋暗挖隧道开挖及后期运营的影响问题,以新大力寺隧道下穿大力寺水库段为工程实例,利用有限元数值模拟分析方法,对不同渗透系数下隧道开挖与水库水渗流综合作用下隧道稳定性进行研究,揭示了水的渗透影响下浅埋隧道失稳机理。
[Abstract]:In this paper, based on the construction of Xindaisi Tunnel in front of the railway from Shangqiu to Hefei (Anhui section), the finite element numerical simulation is used. Based on the combination of field monitoring and theoretical analysis, the key techniques of underpass construction of large cross-section tunnel in complex environment are analyzed and studied, and the reasonable construction method of tunnel underpass in mountain area is determined. The design scheme of blasting excavation is improved, and the construction stability under the tunnel and the influence of the reservoir on the later operation of the tunnel are analyzed. The main works and achievements are as follows: (1) aiming at the construction method of shallow buried tunneling through the existing provincial roads, this paper uses Midas GTS / NX software for finite element simulation analysis, taking Xindusi tunnel underpass 208 provincial road as an engineering example. The stress and deformation characteristics of surrounding rock and supporting structure caused by two step method, three step method, six step CD method and double sidewall guide pit method are studied respectively. Based on the results of numerical simulation and combined with the characteristics of different construction methods, The construction scheme of "six steps CD method for protecting the roof condition of large pipe shed" under the existing provincial tunnel with large cross-section is recommended. The construction of this section is guided, and the field monitoring carried out by tracking the construction verifies the rationality of the recommended scheme. (2) the influence of the traffic load on the stability of the tunnel during the construction of large cross-section passenger tunnel, the numerical analysis shows that, as far as the surrounding displacement analysis of the tunnel is concerned, there is no obvious influence on the surrounding rock displacement by the vehicle operation; In terms of the stress analysis of surrounding rock and lining, the stress of surrounding rock and supporting structure at the intersection of subgrade and tunnel axis is changed, but the change is small. In order to ensure the stability of the tunnel, it is suggested that the surrounding rock in the tunnel within the width of the road should be strengthened and disposed during the construction to ensure the safety of the tunnel construction. (3) the vibration effect caused by the late running of the dart to the new tunnel is discussed. In order to ensure that there is no interaction between existing provincial roads and newly built tunnels during operation, this paper provides a reference basis for the project of highway or railway under tunnels in similar mountain areas in the future. (4) aiming at the vibration effect of excavating tunnel by drilling and blasting method on adjacent ancient buildings, In this paper, the vibration velocity and acceleration of the most dangerous point in Xindangsi tunnel during blasting are analyzed, the blasting scheme of construction is optimized, and the blasting scheme of two optimal construction is compared and analyzed, taking the Xindangsi tunnel under the new Dadaosi tunnel as an engineering example to analyze the vibration velocity and acceleration of the most dangerous point in the tunnel during blasting. Finally, the reasonable and feasible construction blasting scheme is determined, which guides the blasting construction of the tunnel. (5) aiming at the influence of the seepage of reservoir water on the excavation of shallow buried tunnel and its later operation, The tunnel stability under the combined action of tunnel excavation and reservoir water seepage under different permeability coefficients is studied by using finite element numerical simulation analysis method, taking the tunnel under the new Dadaosi tunnel as an engineering example. The instability mechanism of shallow tunnel under the influence of water permeation is revealed.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U455.4

【参考文献】