山底隧道穿越巨厚矿渣层不良地质体的结构稳定性分析

发布时间：2018-01-15 07:24

本文关键词：山底隧道穿越巨厚矿渣层不良地质体的结构稳定性分析　出处：《石家庄铁道大学》2015年硕士论文　论文类型：学位论文

【摘要】：单洞三车道大跨度公路隧道断面多呈扁平状。不良地质段围岩自身稳定性较差,加之扁平大跨度隧道断面形式的影响,施工难度比较大,而且在施工过程中围岩极容易发生失稳破坏。本文以山底隧道为依托,首先对穿越巨厚矿渣层的大跨度隧道的围岩稳定性和施工力学行为进行研究分析。对隧道所穿越区域对应的围岩等级和各围岩对应开挖方法进行详细分析。其次,利用FLAC3D结合隧道工程特点建立3D数值模型,对三台阶七步开挖法开挖过程一个循环进尺各施工步隧道拱顶变形特征、拱脚水平位移以及衬砌支护结构的第一主应力情况进行模拟分析。再次,通过对隧道断面拱顶和拱脚处的监测数据进行回归拟合分析,将监测值与回归拟合值以及数值模拟结果进行对比分析,得到回归拟合曲线的变化规律能够反映围岩变形的规律特征。数值模拟结果与隧道围岩变形基本符合,围岩在施工过程中基本处于稳定状态。最后,经分析得出对巨厚矿渣层段围岩按照破碎带围岩进行处理,采用三台阶七步开挖法是合理的选择。根据地质勘查报告和数值模拟结果采取合理的超前支护方法能够保证围岩稳定,支护结构的力学变化特性均在安全允许范围内。研究结果对类似工程具有一定的参考价值。
[Abstract]:The section of single hole and three lane long span highway tunnel is mostly flat. The stability of surrounding rock of bad geological section is poor, and the influence of plane and long span tunnel section form makes the construction difficult. Moreover, the surrounding rock is vulnerable to instability in the construction process. This paper is based on the tunnel at the bottom of the mountain. Firstly, the stability of surrounding rock and the construction mechanics behavior of the large-span tunnel through the super-thick slag layer are studied and analyzed, and the surrounding rock grade and the corresponding excavation method of each surrounding rock are analyzed in detail. . Based on the 3D numerical model of FLAC3D combined with the characteristics of tunnel engineering, the deformation characteristics of the arch roof of each step tunnel in the excavation process of three steps and seven steps are studied. The horizontal displacement of arch foot and the first principal stress of lining support structure are simulated and analyzed. Thirdly, the monitoring data of tunnel section arch roof and arch foot are analyzed by regression fitting. By comparing the monitoring value with the regression fitting value and the numerical simulation result, the variation law of the regression fitting curve can reflect the regular characteristics of the surrounding rock deformation, and the numerical simulation result is basically consistent with the surrounding rock deformation of the tunnel. The surrounding rock in the construction process is basically in a stable state. Finally, through the analysis of the extremely thick slag section of the surrounding rock in accordance with the broken zone surrounding rock treatment. The three-step seven-step excavation method is a reasonable choice. According to the geological survey report and numerical simulation results, reasonable advance support method can ensure the stability of surrounding rock. The mechanical characteristics of the supporting structure are all within the safe allowable range. The results of the study have certain reference value for similar engineering.
【学位授予单位】：石家庄铁道大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U451

【参考文献】