北京地铁6号线物资学院站车站与隧道区间施工沉降控制技术研究

发布时间：2018-01-16 16:25

本文关键词：北京地铁6号线物资学院站车站与隧道区间施工沉降控制技术研究　出处：《兰州交通大学》2014年硕士论文　论文类型：学位论文

更多相关文章：地铁 地表沉降 变截面 大断面 PBA法

【摘要】：在地铁施工中，区间行车隧道多采用盾构法进行施工，其相关的研究和施工经验已得到大量的总结归纳，日趋完善，但是在隧道区间施工时常会遇到非常规断面隧道的施工。大断面变截面隧道具有较为复杂的特性，其开挖施工时造成的地表的沉降特点往往与普通隧道有较大的差别。在地铁车站施工时，PBA工法在众多工法中得到越来越多的应用。本文以北京地铁6号线二期工程物资学院站的施工建设和施工监测数据为基础，针对一站两区间中的平交段大断面变截面隧道和PBA工法车站的施工，运用Midas/GTS软件进行数值模拟，模拟了不同施工顺序对地表沉降的影响，对比分析实际监测数据和不同工况下的数值模拟结果，分析了不同施工方法对地表沉降的影响。针对变截面大断面隧道施工对地表沉降的影响，根据实际监测数据和数值模拟结果，分析结果产生差异的原因，考虑实际施工情况，本文认为在变截面隧道施工中，沿隧道施工方向的水平位移对地表沉降会产生不可忽视的影响，影响结果使得隧道两端的沉降减少，而变截面位置的沉降较大。在变截面位置，截面埋深差较大的一侧将产生沉降极值，该位置为地表沉降的最不利位置，在施工中应重视该位置的沉降控制。运用数值模拟对变截面隧道的施工顺序进行对比分析时，考虑变截面隧道中由大断面向小断面施工和从小断面向大断面施工两种工况，得出以下结论：由大断面向小断面施工工程中，地表沉降集中在大断面上方，沉降范围较小，沉降最大值较大，从小断面向大断面施工过程中，沉降分布在整个隧道上方，沉降影响范围较大，且由于隧道变换截面，范围内的沉降不均匀，在仅考虑地表沉降的情况下应针对不同地表情况进行施工顺序的设计。 PBA工法是先开挖导洞来进行由桩、墙、拱结构组成的初期支护施工后再开挖整个断面并进行二衬施工的一种施工方法，本文中根据对采用PBA工法的车站的实际监测数据分析，认为采用PBA工法时，对地表沉降影响最大的施工步骤为上层中部导洞和扣拱位置的开挖施工，该步骤造成的沉降量占总沉降量的70%以上。在对PBA工法中不同小导洞施工顺序进行数值模拟，根据模拟结果，本文认为先进行下部导洞施工再进行上部导洞施工能够有效减少导洞开挖对地表沉降的影响，采用不同导洞施工顺序完成导洞施工后，，施工扣拱步骤产生的沉降量基本一致，在扣拱施工完成后车站主体的沉降基本完成，后续施工步骤对车站施工带来的地表沉降影响非常小，控制PBA车站施工对地表沉降影响主要应在导洞施工顺序和扣拱施工时的地表沉降控制等方面着手。
[Abstract]:In the subway construction, the shield method is used in the construction of the interval driving tunnel, and its related research and construction experience have been summarized and summarized, and become more and more perfect. However, the construction of unconventional cross-section tunnel is often encountered in the tunnel section construction. The large-section variable section tunnel has more complex characteristics. The settlement characteristics of the ground caused by the excavation are often different from those of the ordinary tunnel. PBA method has been used more and more in many engineering methods. This paper is based on the construction construction and construction monitoring data of Beijing Metro Line 6 Phase II Engineering Materials Institute Station. Aiming at the construction of large cross-section and variable cross section tunnel and PBA station in the two sections of one station and two stations, the influence of different construction sequence on the surface settlement is simulated by using Midas/GTS software. The actual monitoring data and numerical simulation results under different working conditions are compared and the effects of different construction methods on surface subsidence are analyzed. According to the influence of the construction of large section tunnel with variable cross section on the surface settlement, according to the actual monitoring data and numerical simulation results, the reasons for the difference between the results are analyzed, and the actual construction situation is considered. In this paper, it is concluded that the horizontal displacement along the tunnel construction direction can not be ignored in the construction of the tunnel with variable cross-section, which can not be ignored, and the result of the influence will reduce the settlement at both ends of the tunnel. In the position of variable section, the settlement extreme value will be produced in the side with large depth difference of section, which is the most unfavorable position of surface subsidence. During the construction, the settlement control of this position should be paid attention to, and the construction sequence of the tunnel with variable section should be compared and analyzed by numerical simulation. Considering the construction conditions of variable cross section tunnel from large section to small section and from small section to large section, the following conclusions are drawn: in the construction project from large section to small section, the ground subsidence is concentrated on the top of large section. The settlement range is smaller and the maximum settlement is larger. In the construction process from small section to large section, the settlement is distributed over the whole tunnel, and the settlement is not uniform because of the changing section of the tunnel. The design of construction sequence should be carried out according to different surface conditions only considering ground subsidence. PBA construction method is a kind of construction method which first excavates the guide hole to carry on the initial support construction which is composed of the pile, the wall, the arch structure, then excavates the entire section and carries on the two-lining construction. Based on the analysis of the actual monitoring data of the station with PBA method, the author thinks that the most important construction step for the ground subsidence is the excavation of the upper and middle diversion tunnel and the position of the buckle arch when using the PBA method. The settlement caused by this step is more than 70% of the total settlement. The different construction sequence of small guide tunnel in PBA construction method is numerically simulated, according to the simulation results. In this paper, it is concluded that the lower guide tunnel construction and the upper guide tunnel construction can effectively reduce the influence of the tunnel excavation on the surface settlement, and the different construction sequence of the guide tunnel construction can be used to complete the guide tunnel construction. The settlement of the main body of the station is basically completed after the construction of the arch buckle, and the effect of the subsequent construction steps on the ground surface settlement is very small. In order to control the influence of PBA station construction on surface settlement, the construction sequence of guide tunnel and the control of surface settlement during arch construction should be taken into account.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U231.3;U455.4

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