盾构隧道近接施工对既有隧道的影响分析

发布时间：2018-02-04 21:25

本文关键词： 盾构隧道内力位移近接度影响区与对策 FLAC3D　出处：《中南大学》2014年硕士论文　论文类型：学位论文

【摘要】：本文以长沙轨道交通一号线为工程背景,综合运用调查研究、数值分析、现场测试和经验类比方法,归纳总结盾构隧道近接施工的特殊性和普遍性问题进行研究。主要完成了以下工作： 1)分析了盾构施工过程中盾构、土体以及既有隧道三者共同作用机理,利用FLAC3D建立能够更加全面合理地模拟盾构施工过程中各种影响因素(包括围岩应力释放、盾构开挖面顶推力、盾尾注浆及其凝固等)影响的三维数值计算模型。 2)通过对交叉、并行、交叠隧道3种不同工况进行三维静力数值模拟,获得包括新建隧道施工引起的地表沉降、既有隧道变形和结构内力的变化规律,并对施工引起的既有隧道的结构安全性进行评价。主要得出以下结论,在盾构隧道接近并穿越既有隧道的交叠区域内,将引起既有建筑物的附加内力和变形,对其结构造成不利影响；在该区域以外,施工的影响比较有限。 3)建立平行隧道静力计算模型,对16种工况进行分析,根据近接影响度和影响分区理论,运用统计力学方法,利用地表位移判别准则和结构强度判别准则对近接影响度表达式中的几何近接度影响修正系数αOij,埋深影响的修正系数α4ij和综合系数Kij进行了研究,并得到了基于埋深比(H/D)与净距比(S/D)—几何近接度A的近接影响分区。 4)通过三维数值模拟分析盾构下穿施工引起的营盘路过江隧道及金满地商业街引起结构位移、内力变化规律,同时,根据计算结果提出合理的主动防护措施如地层注浆、玻璃纤维筋围护以及监测方案来抑制地层及结构变形,为以后类似条件下的施工提供一定的借鉴与参考。
[Abstract]:In this paper, Changsha Rail Transit Line 1 as the engineering background, comprehensive use of investigation and research, numerical analysis, field testing and empirical analogy method. The particularity and universality of shield tunnel construction are summarized. The main work is as follows: 1) analyze the interaction mechanism of shield, soil and existing tunnel during shield construction. The establishment of FLAC3D can simulate all kinds of influence factors (including stress release of surrounding rock, top thrust of shield excavating face) in shield construction process more comprehensively and reasonably. A three-dimensional numerical model for the effect of shield-tail grouting and its solidification. 2) through the three-dimensional static numerical simulation of three different working conditions of cross tunnel, parallel tunnel and overlapping tunnel, the surface settlement caused by new tunnel construction, the variation law of tunnel deformation and structure internal force are obtained. And the structural safety of the existing tunnel caused by construction is evaluated. The following conclusions are drawn: the additional internal force and deformation of the existing building will be caused by the shield tunnel approaching and passing through the overlapping area of the existing tunnel. (B) adversely affecting its structure; Outside the area, the impact of construction is relatively limited. 3) the static calculation model of parallel tunnel is established, and the 16 working conditions are analyzed. According to the influence degree of close connection and the theory of influence zoning, the statistical mechanics method is used. The surface displacement criterion and the structural strength criterion are used to determine the effect of geometric proximity on the correction coefficient 伪 Oij in the expression of the influence degree of near connection. The correction coefficient 伪 4ij and the synthesis coefficient Kij of the buried depth effect are studied, and the influence zones based on the buried depth ratio (H / D) and the net distance ratio (S / D) are obtained. 4) the structural displacement and internal force caused by shield tunneling and Jinmandi commercial street are analyzed by three-dimensional numerical simulation. At the same time. According to the calculation results, reasonable active protective measures such as stratum grouting, glass fiber reinforcement enclosure and monitoring scheme are put forward to restrain formation and structure deformation, which can be used for reference and reference for construction under similar conditions in the future.
【学位授予单位】：中南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U455.43

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