流固耦合作用下北京朝阳区富水地层隧道施工的力学效应研究

发布时间：2018-03-16 07:25

本文选题：PBA工法　切入点：CRD工法　出处：《中国地质大学(北京)》2017年硕士论文　论文类型：学位论文

【摘要】：地铁隧道的出现很好的缓解了城市交通的压力,但是由于地下空间的大规模开发,地铁隧道不可避免的要穿越一些高水位的富水软弱地层区域。在这种情况下,地下渗流会对隧道施工造成极大的影响,例如:加大土层和周边建筑的固结沉降量、造成地表的不均匀沉降和围岩的不均匀变形等。然而,为了简化计算过程,目前在研究隧道施工时常选择忽略地下水的影响,因此该方向的研究还不成熟。本文以北京市朝阳区CRD法开挖的地下通道和PBA法开挖的地铁车站为背景,研究了地下水-围岩-隧道支护结构三者的流固耦合效应(FSI)和力学效应,主要工作与研究内容如下所示:(1)简要阐述饱和土的渗流理论,并基于渗流连续性方程和比奥(Biot)固结理论推导土体三维渗流场和应力场耦合的微分方程。(2)对暗挖隧道地表沉降、拱顶变形、洞壁收敛、初支压力及洞内渗水情况等数据进行收集与筛选,选择适合于计算、分析的典型断面。(3)简要介绍显式有限差分元软件FLAC~(3D)中关于渗流与应力耦合的数值表达方式。运用FLAC~(3D)流固耦合计算模式模拟两个隧道的施工过程,分别在考虑与不考虑流固耦合的情况下建立数值模型,计算不同导洞施工顺序的情况下CRD和PBA隧道地表沉降和围岩及支护结构的变形与受力情况,对比不同情况下位移场、应力场和渗流场变化过程,得出地下水对于隧道开挖造成的影响。(4)对比分析朝阳六里屯地下通道施工监测数据,验证数值模拟的合理性,并评价隧道施工的安全性,得出的结果可为后续施工提供指导和借鉴。(5)运用得到的研究经验,对同地区的朝阳公园地铁站展开研究,探究在洞桩法施工的条件下,地下水对不同导洞施工顺序造成的影响。
[Abstract]:The emergence of subway tunnels has alleviated the pressure on urban traffic. However, due to the large-scale development of underground space, subway tunnels inevitably have to cross some high water level areas of water-rich soft strata. In this case, Underground seepage will have a great impact on tunnel construction, such as increasing the consolidation settlement of soil layer and surrounding buildings, causing uneven settlement of the surface and non-uniform deformation of surrounding rock, etc. However, in order to simplify the calculation process, At present, the influence of groundwater is often ignored in the study of tunnel construction, so the research in this direction is not mature. This paper takes the underground passage excavated by CRD method and the subway station excavated by PBA method in Chaoyang District of Beijing as the background. The fluid-solid coupling effect (FSI) and mechanical effect of groundwater, surrounding rock and tunnel supporting structure are studied. The main work and research contents are as follows: (1) the seepage theory of saturated soil is briefly described. Based on the continuity equation of seepage flow and Biotot's consolidation theory, the differential equation of coupling three dimensional seepage field and stress field of soil is derived. Data such as initial branch pressure and water seepage in the tunnel are collected and screened, and suitable for calculation is selected. The numerical expression of seepage and stress coupling in explicit finite difference element software FLAC3D is briefly introduced. The fluid-solid coupling calculation model is used to simulate the construction process of two tunnels. In this paper, numerical models are established with or without consideration of fluid-structure coupling to calculate the ground subsidence, deformation and stress of surrounding rock and supporting structure of CRD and PBA tunnels under different construction sequence of guide tunnel, and the displacement field under different conditions is compared. The variation process of stress field and seepage field is obtained. The influence of groundwater on tunnel excavation is obtained.) the construction monitoring data of Chaoyang Liulitun underground tunnel are compared and analyzed, the rationality of numerical simulation is verified, and the safety of tunnel construction is evaluated. The results can provide guidance and reference for further construction. Using the research experience obtained, the paper studies the subway station of Chaoyang Park in the same area, and probes into the influence of underground water on the construction sequence of different diversion tunnels under the condition of tunnel pile construction.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U451;U231

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