城市地铁浅埋暗挖隧道初期支护结构受力特征及围岩稳定性研究

发布时间：2018-03-03 13:55

本文选题：隧道　切入点：浅埋暗挖　出处：《安徽建筑大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着我国城市规模的不断扩大和经济建设的飞速发展,城市化问题越来越严重,轨道交通在解决城市交通问题中扮演重要的角色。目前国内外城市地铁地下隧道施工多以盾构法施工法为主,但对特殊地段和部位因施工环境所限,采用浅埋暗挖工法施工的隧道工程也为数不少。与盾构法施工相比,浅埋暗挖隧道施工具有上覆岩土层薄,对地面环境影响大,围岩受力复杂,安全隐患多等特点。因此,开展本论文研究,对指导工程安全施工具有重要的理论意义和应用价值。论文以合肥地铁2号线的某一隧道断面为研究背景,采用隧道理论计算、有限元数值模拟分析和监测数据分析相结合的方法,对浅埋暗挖隧道结构的支护受力特征和围岩稳定性等方面进行了研究,研究的主要内容和成果如下:1根据国内外研究的现有资料,对隧道围岩变形和支护结构的公式推导,确定地铁浅埋暗挖隧道的围岩压力,以及隧道衬砌结构受力大小及特征。2通过大量的工程实例并结合理论推导,得出支护结构在围岩压力作用下的计算公式适用于浅埋暗挖隧道。并应用合肥地铁工程实例进行对理论公式进行验算校核。3通过建立二维数值模型模拟CRD法和双侧壁导坑法施工,对比分析此两种方法比较不同施工方法的隧道开挖时地表沉降变化,初期支护的内力特征和位移规律,提取隧道模型的计算结果,以及在不同工法开挖下引起的隧道的变形隧道初期支护下的轴力和弯矩、水平收敛位移、拱顶下沉位移、隧底隆起位移,分析变化规律,得出初步结论。4二维数值模型模拟CRD法和双侧壁导坑法施工,提取结果以围岩位移场、应力场和初期支护结构内力值。对CRD法和双侧壁导坑法这两种施工方法对比分析,发现这两种方式在位移场控制方面差别不是很大,但在围岩应力场和支护结构内力方面,双侧导坑法优于CRD法。5通过建立浅埋暗挖隧道施工的三维数值模型,并与监测数据进行对比分析,得出此种结构的地表沉降规律,初期支护的受力特征和洞内净空收敛、拱顶沉降和地面沉降的变化规律,可指导类似隧道工程的施工。6通过实际监测数据和数值模拟结果的对比分析,得出三维数值模拟结果是合理的,以及在开挖时期对开挖尺度和开挖进度的控制,并做到边开挖边支护的保护措施。各项位移的规律和最大位移值基本是吻合的,说明了数值模拟的结果是正确合理的。
[Abstract]:With the continuous expansion of urban scale and the rapid development of economic construction in China, the problem of urbanization is becoming more and more serious. Rail transit plays an important role in solving urban traffic problems. At present, shield method is the main method in the construction of underground tunnels in cities at home and abroad, but the special areas and parts are limited by the construction environment. Compared with shield tunneling, shallow tunneling has the characteristics of thin overlying rock and soil layer, great influence on ground environment, complex stress on surrounding rock, and many hidden safety problems. The research of this paper has important theoretical significance and application value for guiding engineering safety construction. This paper takes a tunnel section of Hefei Metro Line 2 as the research background and adopts tunnel theory calculation. By combining finite element numerical simulation analysis with monitoring data analysis, the supporting force characteristics and surrounding rock stability of shallow tunneling structure are studied. The main contents and results of the study are as follows: 1 according to the existing research data at home and abroad, the deformation of tunnel surrounding rock and the formula of supporting structure are deduced, and the surrounding rock pressure of shallow buried tunnel is determined. As well as tunnel lining structure force size and characteristics .2 through a large number of engineering examples and combined with theoretical derivation, It is concluded that the formula of supporting structure under the action of surrounding rock pressure is suitable for shallow burying tunnel, and the theoretical formula is checked and checked by the example of Hefei metro project. 3. Through establishing two dimensional numerical model to simulate CRD method and double tunnel. Sidewall pit construction, Comparing these two methods with different construction methods, the surface subsidence, the internal force characteristics and the displacement law of the initial support are compared, and the calculated results of the tunnel model are extracted. The axial force and bending moment, horizontal convergent displacement, arch sinking displacement, bottom uplift displacement of the tunnel deformation caused by different excavation methods under the initial support of the tunnel are analyzed. Conclusion .4 Two-dimensional numerical model is used to simulate the construction of CRD method and double-sidewall tunnel method, and the results are obtained from the displacement field of surrounding rock, stress field and internal force of initial supporting structure. The comparison and analysis of two construction methods, CRD method and double-sidewall tunnel method, are made. It is found that the two methods are not very different in the control of displacement field, but in the stress field of surrounding rock and the internal force of the supporting structure, the double-side pit method is superior to the CRD method in establishing the three-dimensional numerical model of shallow tunneling construction. By comparing and analyzing with the monitoring data, the law of surface subsidence of this kind of structure, the stress characteristics of initial support and the convergence of clearance in the tunnel, the variation law of vault settlement and land subsidence are obtained. Through the comparison and analysis of actual monitoring data and numerical simulation results, it can be concluded that the three-dimensional numerical simulation results are reasonable, and the excavation scale and schedule are controlled during the excavation period. The law of displacement is basically consistent with the maximum displacement value, which shows that the results of numerical simulation are correct and reasonable.
【学位授予单位】：安徽建筑大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U231.3;U451

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