浅埋暗挖地铁隧道施工变形研究

发布时间：2018-02-25 07:04

本文关键词： 地铁隧道浅埋暗挖数值模拟灰关联分析　出处：《兰州交通大学》2017年硕士论文　论文类型：学位论文

【摘要】：经济高速发展的今天,能不能拥有更为便利、快捷的交通已经越来越成为制约地区经济发展的关键。发展以地铁为主的城市轨道交通作为解决城区交通拥堵问题解决方式已经越来越多的被运用于我国的大中型城市,兰州地区地质情况特殊,地铁修建过程往往伴随着着地表沉降、拱顶沉降、周边收敛、隧道底部隆起、建筑物变形、深层沉降、地表水平位移、衬砌变形和地下管线变形等。地层的沉降可能引起地表开裂甚至塌陷,同时,地层的沉降也会使地下市政管线随地层而沉降,而不均匀的沉降则会导致管线的渗漏甚至破裂;另外,土层的不均匀沉降还会导致地上建筑物倾斜、开裂变形等。所以对于地表、地层的变形规律研究就具有其现实意义。本文以兰州地铁浅埋暗挖区间隧道为背景,对浅埋暗挖地铁隧道施工过程进行了数值分析模拟,并结合隧道修建过程中第三方监测的实测数据进行了变形预测分析。本文主要研究内容及成果如下:(1)分析总结了现场监测数据,隧道开挖的超前影响约占最终沉降值的5%~10%,左右线隧道相继开挖期间的沉降量约占最终沉降量的55~80%;开挖完成后沉降值约占最终沉降量的12~28%,开挖阶段的沉降变形是地表沉降变形的主要部分,合理的控制台阶长度,并尽量缩短衬砌封闭成环时间能有效控制地表沉降。(2)运用不同类型的函数对地表沉降、拱顶沉降、水平收敛实测数据进行拟合回归分析,并且预测了最终变形值。从拟合的效果来看,Boltzmann函数对于地表变形、拱顶沉降都表现出更好的相关性,倒指数函数对于收敛的则表现出更好的相关性。运用PECK公式进行了地表横向变形的回归分析。(3)结合兰州地铁一号线拱星墩~焦家湾区间浅埋暗挖段工程实例,参考实际施工情况,运用有限元分析软件GTS-NX建立三维实体模型,对施工过程引起的地表、地层沉降变形分纵向和横向进行了研究总结。(4)对数值模拟和现场监测数据进行了对比分析,从结果来看二者所反应测点的变形规律基本一致,可以通过数值分析可以来超前预测隧道施工引起的地层的沉降规律。做了现场围岩及支护结构的现场测试,得出了围岩与初支的接触压力及格栅拱架中钢筋受力规律。(5)采用二维数值模拟方式分析了双线隧道净距、衬砌的弹性模量、围岩的弹性模量以及隧道的埋深对地表变形的影响,并对地表变形规律做了总结。采用灰关联分析法对不同影响因素下的地表最大沉降变形进行了敏感性分析,从关联度序列中可以看出,影响地表最大沉降值的诸多因素中,隧道埋深的影响最大,其次分别是衬砌混凝土弹性模量、围岩弹性模量、双线隧道净距。
[Abstract]:Today, when the economy is developing at a high speed, can it be more convenient? Rapid traffic has become the key to restrict the regional economic development. The development of subway based urban rail transit as a solution to the problem of urban traffic congestion has been used in more and more large and medium-sized cities in China. The geological conditions of Lanzhou area are special. The construction process of subway is often accompanied by ground subsidence, dome settlement, circumjacent convergence, tunnel bottom uplift, building deformation, deep settlement, surface horizontal displacement, etc. Lining deformation and underground pipeline deformation. Ground settlement may cause surface cracking or even collapse, at the same time, stratum settlement will also make underground municipal pipeline layer and settlement, and uneven settlement will lead to pipeline leakage or even rupture; In addition, the uneven settlement of the soil layer will also lead to the slope of the ground building, cracking and deformation, etc. Therefore, for the ground surface, the study of the deformation law of the ground has its practical significance. This paper takes the shallow buried underground tunnel of Lanzhou Metro as the background. Numerical analysis and simulation of the construction process of shallow buried underground subway tunnel are carried out. Combined with the measured data of the third party monitoring during the tunnel construction, the deformation prediction analysis is carried out. The main contents and results of this paper are as follows: 1) the field monitoring data are analyzed and summarized. The advance influence of tunnel excavation accounts for about 5% of the final settlement value. The settlement of the left and right tunnels during successive excavation accounts for 55% of the final settlement. After excavation, the settlement value accounts for about 12% of the final settlement, and the settlement deformation in the excavation stage is the ground. The main part of surface subsidence and deformation, The surface subsidence can be effectively controlled by controlling the length of the steps reasonably and shortening the closing time of the lining.) by using different types of functions, the measured data of surface subsidence, dome settlement and horizontal convergence are analyzed by fitting regression analysis. And the final deformation value is predicted. The Boltzmann function shows a better correlation to the surface deformation and the dome settlement. The inverse exponential function shows a better correlation to convergent ones. The regression analysis of the transverse deformation of the ground surface is carried out by using the PECK formula. Combined with the engineering example of the shallow buried subsurface excavation section between the arch star pier and Jiaojia Bay section of Lanzhou Metro Line 1, Referring to the actual construction situation, using the finite element analysis software GTS-NX to set up the three-dimensional solid model, for the surface caused by the construction process, The paper compares and analyzes the numerical simulation data and the field monitoring data. The results show that the deformation law of the measured points is basically the same. Numerical analysis can be used to predict the settlement law of strata caused by tunnel construction in advance. The site test of surrounding rock and supporting structure has been done. The contact pressure between surrounding rock and initial support and the stress law of reinforcement in grid arch frame are obtained. The effects of net distance, elastic modulus of lining, elastic modulus of surrounding rock and buried depth of tunnel on surface deformation are analyzed by two-dimensional numerical simulation. In this paper, the law of surface deformation is summarized. The sensitivity analysis of surface maximum settlement under different influence factors is carried out by using grey correlation analysis. From the correlation degree series, it can be seen that among the many factors that affect the maximum subsidence value of the surface, The influence of tunnel depth is the most, followed by the elastic modulus of lining concrete, the elastic modulus of surrounding rock and the net distance of double-line tunnel.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U456.3;U231.3

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