螺旋隧道开挖方法及设计参数优化研究

发布时间：2018-03-13 07:17

本文选题：螺旋隧道　切入点：有限元法　出处：《重庆交通大学》2016年硕士论文　论文类型：学位论文

【摘要】：隧道建设受到地形、地质等条件限制,利用自然展线或长大隧道都无法克服线路控制点间的高差时,螺旋隧道具有更好的线形条件和满足线形指标的潜能,越来越受到重视。但螺旋隧道的应用还比较少,需要进行深入研究。本文基于重庆市渝中区大化路螺旋隧道这一工程背景,采用有限元方法,对螺旋隧道的线形曲率、开挖方法、左右线工作面间距、施工监测等方面进行了详细的研究,主要的研究内容及结论如下:(1)确定了螺旋隧道最佳曲线半径。螺旋隧道随着线形半径的减小表现出以下规律:围岩受力越来越差;围岩塑性区由无到有,塑性区面积不断增大;隧道衬砌表现出的不对称变形越来越明显,初支体系受力增大。当受条件所限必须采用螺旋隧道形式时,建议结合地形条件尽量选取较大的线形半径,使线形相对平缓。(2)确定了合理的开挖方法。通过对全断面法、台阶法、CD法三种工法下螺旋隧道受力及变形分析可得:开挖过程中,围岩及初支结构的变形在三种工法下近似,且均没有出现塑性区,其中CD法下围岩及初支结构的变形略小,体现出一定的控制围岩变形的能力;从初支结构受力情况得出三种工法从优到差的顺序依次是CD法、台阶法、全断面法。考虑到螺旋隧道的受力不对称性,应选用变形较为平缓的施工方法,避免急促变形的出现,以免引起围岩失稳。(3)确定了隧道左右线施工开挖面的安全间距。左右线施工间距对围岩及初支结构最终的累计变形及受力影响较小。但是,围岩及初支结构在变形过程中受到的影响较大,当左右线施工间距为5m时,隧道变形过程有波动,这是由于左右洞之间的相互影响导致。随着左右线施工间距的增大,如间距为15m和25m时,隧道关键点变形曲线未出现波动,左右洞之间的相互影响很小。(4)通过对比数值模拟结果与现场监控量测数据,隧道变形趋势近似,论证了数值模拟研究的正确性。在推荐的大化路隧道设计及施工方法下,隧道超前洞和后续洞的拱顶沉降、水平收敛,累计变形量均未超过规范规定的允许变形量,大化路隧道设计及施工方案可行。(5)通过以上研究结论,对重庆市渝中区大化路螺旋隧道的设计施工具体指导意义。
[Abstract]:The tunnel construction is restricted by topography, geology and so on. When the height difference between the control points can not be overcome by the natural extension or the long tunnel, the spiral tunnel has better linear conditions and the potential to meet the linear index. More and more attention has been paid to the spiral tunnel, but the application of spiral tunnel is relatively few, which needs further study. Based on the engineering background of Dahua Road Spiral Tunnel in Yuzhong District of Chongqing City, this paper adopts finite element method to study the linear curvature of spiral tunnel. The excavation method, the distance between the right and left faces, the construction monitoring and so on are studied in detail. The main research contents and conclusions are as follows: (1) the optimum curve radius of spiral tunnel is determined. With the decrease of linear radius, the spiral tunnel shows the following laws: the stress of surrounding rock is getting worse and worse, the plastic zone of surrounding rock increases from zero to having, the area of plastic zone increases continuously; The asymmetric deformation of tunnel lining is becoming more and more obvious, and the initial branch system is subjected to more and more stress. When the tunnel must be in the form of spiral tunnel under limited conditions, it is suggested that a larger linear radius should be chosen as far as possible in combination with topographic conditions. The reasonable excavation method is determined by making the line shape relatively smooth. Through the analysis of the stress and deformation of the spiral tunnel under the three methods of full section method, step method and CD method, the deformation of the surrounding rock and the initial branch structure is approximate under the three kinds of engineering methods during the excavation. There is no plastic zone in all of them, in which the deformation of surrounding rock and primary branch structure under CD method is slightly smaller, which reflects the ability to control the deformation of surrounding rock, and from the stress situation of initial support structure, it is concluded that the order of three kinds of engineering methods is CD method, step method, and so on. Full section method. Considering the asymmetry of spiral tunnel force, the construction method with gentle deformation should be chosen so as to avoid the appearance of rapid deformation. In order to avoid the instability of surrounding rock, the safe distance of excavation surface is determined. The distance between left and right lines has little effect on the accumulative deformation and force of surrounding rock and initial support structure. However, The surrounding rock and the initial support structure are affected greatly in the deformation process. When the construction distance of the left and right lines is 5 m, the tunnel deformation process fluctuates, which is caused by the mutual influence between the left and right tunnels. With the increase of the construction distance between the left and right lines, For example, when the spacing is 15m and 25m, the deformation curve of the key points of the tunnel does not fluctuate, and the interaction between the left and right tunnels is very small. The correctness of numerical simulation study is demonstrated. Under the recommended design and construction method of Dahua Road Tunnel, the settlement of the arch roof of the leading tunnel and the subsequent tunnel is horizontal convergent, and the cumulative deformation amount is not more than the allowable deformation amount stipulated in the code. The design and construction scheme of Dahua Road Tunnel is feasible. Through the above conclusions, it is of guiding significance to the design and construction of Dahua Road Spiral Tunnel in Yuzhong District of Chongqing City.
【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】：U455.4

【相似文献】