地铁隧道盾构施工引起土体附加应力及地表沉降研究

发布时间：2018-02-10 00:55

本文关键词： 地铁隧道盾构开挖附加应力场地表沉降 Peck公式随机介质理论参数反演数值模拟　出处：《中南大学》2014年硕士论文　论文类型：学位论文

【摘要】：摘要：随着全国城市地下轨道建设的兴起,地铁隧道盾构开挖由于其广泛的地层适用性以及经济优越性而得到迅速的发展,成为全国各大城市地铁建设的首要选择。为研究盾构开挖对周围土体影响,控制地铁隧道盾构开挖对地表沉降变形以及对周围建筑物变形影响,需要对隧道盾构开挖所引起的周围土体附加应力以及地表沉降规律进行分析,获得区域性盾构施工经验,为类似地层地铁隧道盾构施工提供理论背景,以确保盾构开挖时地表建筑物的安全性和适用性。本文结合南京三号线常府街-夫子庙区间地铁隧道土压平衡式盾构施工项目,采用弹性理论解研究了隧道盾构开挖对周围土层产生的附加应力场；运用随机介质理论、Peck公式以及数值计算分析了隧道盾构开挖所引起的地表以及建筑物沉降变形。本文主要研究内容如下： 1.对隧道开挖区间段盾构施工参数以及地表沉降值进行统计分析,并结合统计结果评价盾构施工在所研究土层段的施工质量；整理所研究开挖区间段地表纵向及横向沉降测点实测沉降值,获得了完整的现场实测资料。 2.结合南京地铁三号线常府街-夫子庙区间段右线盾构开挖实例,采用弹性力学Mindlin公式在土体中一点的应力解以及源汇法,对盾构施工区域面积进行积分,获得盾构开挖面附加推力、盾壳与周围土体之间的摩擦力以及盾尾土体损失对周围土体所引起的附加应力场分布区域以及规律。 3.结合隧道盾构开挖导致的地面纵向沉降点按施工时序所产生的沉降曲线,分析了盾构推进时地表沉降五个阶段的变化规律。应用Peck公式、随机介质理论,分别通过最小二乘法、Powell优化法反演其纵向沉降公式计算参数,并正算隧道盾构开挖所导致的地表横向沉降曲线并与实测横向沉降曲线进行对比,所得结果与实测值基本一致,证实了所获得的反演参数的正确性,能用以指导盾构施工。考虑地表沉降槽范围内建筑物结构刚度对地表沉降槽分布的影响,结合工程实例,利用修正的Peck公式计算建筑物沉降曲线,并与Peck公式计算地表沉降曲线进行对比分析,得出修正Peck公式计算结果更接近现场实测值。 4.应用大型通用有限元软件ABAQUS建立三维模型分析了双线隧道盾构施工分步开挖导致周围土体附加应力分布规律,以及其对地表沉降的影响,并与理论计算值以及实测值进行对比分析以指导施工。图78幅,表34个,参考文献91篇
[Abstract]:Absrtact: with the rise of urban underground track construction in China, shield tunneling of subway tunnel has been developed rapidly because of its wide ground applicability and economic superiority. In order to study the influence of shield excavation on surrounding soil mass, to control the influence of shield excavation on ground subsidence and deformation of surrounding buildings, It is necessary to analyze the additional stress of surrounding soil and the law of ground subsidence caused by shield tunneling in order to obtain the experience of regional shield construction and provide the theoretical background for the shield construction of subway tunnel in similar strata. In order to ensure the safety and applicability of the surface buildings during shield excavation, this paper combines the earth pressure balance shield construction project of the subway tunnel in Changfujie-Fuzimiao section of Nanjing No.3 line. The additional stress field caused by shield tunneling is studied by using elastic theory. The surface and building settlement deformation caused by shield tunneling is analyzed by using Peck formula of stochastic medium theory and numerical calculation. The main contents of this paper are as follows:. 1. Statistical analysis of shield construction parameters and surface settlement value of tunnel excavation section, and evaluation of the construction quality of shield construction in the studied soil layer combined with statistical results; The measured settlement values of the longitudinal and transverse settlement measuring points in the excavation section are sorted out, and the complete field measured data are obtained. 2. With the example of shield excavation in the section of Changfujie Fumiao section of Nanjing Metro Line No. 3, the area of shield construction area is integrated by using the stress solution of one point of elastic mechanics Mindlin formula in soil and the method of source and sink. The additional thrust of shield excavation surface, the friction between shield shell and surrounding soil, and the distribution of additional stress field caused by the loss of shield tail soil to surrounding soil are obtained. 3. According to the settlement curve produced by the construction time series, the variation law of the five stages of ground subsidence during shield tunneling is analyzed. The Peck formula and stochastic medium theory are applied to analyze the variation of the ground longitudinal settlement points caused by shield tunneling. The parameters of the longitudinal settlement formula are inversed by the least square method and Powell's optimization method respectively, and the transverse settlement curves caused by shield tunneling are calculated and compared with the measured transverse settlement curves. The results are in good agreement with the measured values. It is proved that the obtained inversion parameters are correct and can be used to guide shield construction. Considering the influence of structural stiffness on the distribution of ground subsidence trough in the range of ground subsidence trough, the paper combines with an engineering example. The modified Peck formula is used to calculate the settlement curve of buildings and compared with the Peck formula to calculate the surface settlement curve. The calculated results of the modified Peck formula are closer to the field measured values. 4. The three-dimensional model is established by using ABAQUS, which is a general finite element software. The distribution law of additional stress in surrounding soil caused by two-line shield tunneling and its influence on surface settlement are analyzed. In order to guide construction, 78 figures, 34 tables and 91 references were compared with theoretical calculated values and measured values.
【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;U231.3

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