超大断面连拱隧道合理施工方法与支护参数优化研究

发布时间：2018-03-15 22:00

本文选题：偏压　切入点：双连拱隧道　出处：《重庆交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：公路连拱隧道作为一种特殊的结构形式,具有受地形条件限制小,线形顺畅,引线占地少,跨度大,空间利用率高,结构整体性好以及综合造价低等特点。但由于连拱隧道自身结构的特点,施工期间围岩、隧道结构的受力状况都十分复杂,影响连拱隧道在施工期间和运行稳定性。因此,有必要对连拱隧道的施工过程进行研究。本文依托四川省阆中市嘉陵江四桥连接线东山连拱隧道工程,应用有限元软件ABAQUS对隧道施工分步开挖过程进行了有限元数值分析,对偏压作用下双连拱隧道在整个施工过程的力学行为进行了分析研究,具体工作如下:①针对隧道不同的开挖顺序,进行了六种方案的动态数值模拟,详细分析了围岩应力的变化情况、中隔墙和衬砌的应力状态以及锚杆的受力特点。②将六种模拟方案分组,对比分析不同施工方案各关键工序的模拟结果,得到偏压作用下连拱隧道施工的优选方案为(方案一)先右后左的上台阶中隔壁法。③综合分析各模拟方案,得到双连拱隧道施工过程中,围岩应力分布、中隔墙和支护结构受力变化的规律,指出施工期间围岩在隧道拱顶及底部受力较大,中隔墙在隧道先开挖一侧的压应力大于后开挖一侧的应力,与中隔墙交接处的衬砌受力复杂,易发生破坏。④从改变锚杆数量和长短的角度,计算分析围岩应力分布、中隔墙的受力情况,对连拱隧道支护参数进行优化,得出锚杆数量减少及长度减少一米后,隧道围岩及支护受力均满足设计及安全要求。
[Abstract]:As a special structural form, highway multi-arch tunnel has the advantages of small limitation of terrain, smooth alignment, small lead occupation, large span and high space utilization ratio. The structural integrity is good and the comprehensive cost is low. However, due to the structural characteristics of the multi-arch tunnel itself, the stress state of the surrounding rock and the tunnel structure during construction is very complicated, which affects the stability of the multi-arch tunnel during construction and operation. It is necessary to study the construction process of the multi-arch tunnel. Based on the Dongshan double-arch tunnel project of Jialing River 4th Bridge connecting line in Langzhong City, Sichuan Province, the finite element software ABAQUS is used to carry out the finite element numerical analysis on the excavation process of the tunnel construction step by step. The mechanical behavior of double-arch tunnel under biasing pressure is analyzed and studied in the whole construction process. The concrete work is as follows: 1. According to the different excavation sequence of the tunnel, the dynamic numerical simulation of six schemes is carried out. The variation of surrounding rock stress, the stress state of middle partition wall and lining and the stress characteristics of anchor rod are analyzed in detail. 2. The six simulation schemes are grouped, and the simulation results of each key process of different construction schemes are compared and analyzed. It is obtained that the optimal construction scheme of multi-arch tunnel under biasing pressure is as follows: (scheme one) the next door method in the upper steps, which is first right and left, synthetically analyzes the simulation schemes, and obtains the stress distribution of surrounding rock in the construction process of double-arch tunnel. The law of stress variation of middle partition wall and supporting structure is pointed out. It is pointed out that the stress of surrounding rock on the top and bottom of tunnel arch during construction is great, and the compressive stress of middle partition wall on the side of tunnel excavation is greater than that on the side of tunnel excavation later. The lining at the junction with the middle partition wall is complicated in force, and it is easy to break .4 from the angle of changing the number and length of the anchor rod, the stress distribution of surrounding rock and the stress situation of the middle partition wall are calculated and analyzed, and the supporting parameters of the multi-arch tunnel are optimized. It is concluded that after the reduction of bolt number and length by one meter, the surrounding rock and supporting forces of the tunnel can meet the design and safety requirements.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U455.4

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