不同埋深隧道围岩稳定性问题研究

发布时间：2018-04-02 22:03

本文选题：隧洞　切入点：破坏机理　出处：《重庆交通大学》2014年硕士论文

【摘要】：铁路、公路、城市地铁及城市建设等领域修建了大量的隧洞与地下工程，在这种情况下对于隧洞与地下工程的稳定性研究就显得更为重要。当前人们对隧洞失稳破坏判据的研究尚不成熟，依据不同的失稳判据一般会得出不相同的稳定安全度，如何建立一个既具有理论基础又与工程实际相符，既能够反映隧洞的破坏本质，又不受其他因素干扰的稳定性定量判据是十分必要的。而对隧洞的破坏机理开展研究是提出一种科学合理的失稳破坏判据的首要前提。故本文主要采用了有限元强度折减法对不同埋深隧洞的稳定性问题进行研究，并对其破坏机理进行探讨。 ①总结了当前国内外地下工程围岩稳定性的研究现状，，并分析了隧洞围岩的破坏机理，推导了圆形隧洞围岩的塑性滑移线方程；对围岩压力理论和压力的解析计算和数值计算进行了概要性介绍。 ②对有限元极限分析法的原理和基本理论进行了总结，选取了适合于有限元强度折减法的本构模型、屈服准则及流动法则，简要介绍了有限元非线性分析的三种基本方法，并对DP4屈服准则与DP1屈服准则下安全系数的转换公式进行了推导，介绍了一种在ANSYS中实现DP4屈服准则的方法。 ③介绍了几种主要的隧洞围岩稳定性判据，包括围岩的极限位移和极限应变判据、围岩塑性区大小判据，分析这些判据的缺陷并介绍了更为合理的围岩安全系数判据。 ④分别建立同面积的圆形、马蹄形、矩形断面隧洞模型，并分析它们在相同围岩条件下的围岩安全系数各自随不同埋深的变化规律，分析表明圆形、马蹄形这类拱形隧洞与同样埋深条件下的矩形隧洞相比具有更高的安全系数。 ⑤从分析结果可以看出隧洞在浅埋时表现出比深埋时更大的安全系数，这可能与工程实际不相符。分析了产生这个问题的原因，并给出了解决该问题的建议。 ⑥以重庆市轨道交通所经隧道—中梁山隧道为依托，对围岩安全系数采用有限元强度折减法计算，而衬砌安全系数按结构力学方法进行计算。分别研究分析了围岩、变电所初衬及正洞隧道二衬的安全系数的变化规律。
[Abstract]:A large number of tunnels and underground projects have been built in the fields of railway, highway, urban subway and urban construction. In this case, it is more important to study the stability of tunnels and underground projects.At present, the research of tunnel instability failure criterion is not mature. According to different instability criterion, different stability and safety degree can be obtained. How to establish a tunnel failure criterion is not only theoretical foundation but also accord with engineering practice.It is necessary that the quantitative criterion of stability can reflect the nature of tunnel failure and not be disturbed by other factors.The research on the failure mechanism of tunnel is the first prerequisite to propose a scientific and reasonable criterion of instability failure.In this paper, the finite element strength reduction method is used to study the stability of tunnels with different buried depths, and the failure mechanism is discussed.The main contents are as follows: (1) the present research status of surrounding rock stability of underground engineering at home and abroad is summarized, and the failure mechanism of surrounding rock of tunnel is analyzed, and the plastic slip line equation of surrounding rock of circular tunnel is deduced.The theory of surrounding rock pressure and the analytical and numerical calculation of surrounding rock pressure are briefly introduced in this paper.Secondly, the principle and basic theory of finite element limit analysis are summarized. The constitutive model, yield criterion and flow rule suitable for finite element strength reduction method are selected, and three basic methods of nonlinear finite element analysis are introduced briefly.The conversion formula of safety factor under DP4 yield criterion and DP1 yield criterion is deduced, and a method to realize DP4 yield criterion in ANSYS is introduced.3. Several main criteria for the stability of surrounding rock in tunnel are introduced, including the criterion of limit displacement and limit strain of surrounding rock, the criterion of plastic zone of surrounding rock, the defect of these criteria and the more reasonable criterion of safety factor of surrounding rock.(4) the tunnel models of circular, horseshoe and rectangular sections with the same area are established, and the variation law of the safety factor of surrounding rock with different burial depth under the same surrounding rock condition is analyzed.Compared with the rectangular tunnel with the same buried depth, the horseshoe arch tunnel has a higher safety factor.(5) from the analysis results, it can be seen that the tunnel shows a greater safety factor in shallow burying than in deep burying, which may not be in accord with the engineering practice.The causes of this problem are analyzed, and some suggestions to solve the problem are given.The safety factor of surrounding rock is calculated by finite element strength reduction method, and the safety factor of lining is calculated according to the structural mechanics method based on the tunnel of Chongqing Railway Transportation Institute-Zhongliangshan Tunnel.The variation law of safety factor of surrounding rock, primary lining of substation and second lining of Zhengdong tunnel is studied and analyzed respectively.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U451.2

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