【作者】 肖林萍；

【导师】 李永树；

【作者基本信息】 西南交通大学 ， 大地测量学与测量工程， 2009， 博士

【摘要】 近年来我国高速公路处于快速发展时期。在我国中西部山岭地区由于受地形和地质条件限制,许多越山公路选用了连拱隧道。连拱隧道由于跨度较大、结构复杂,其稳定性是目前研究的热点问题,尤其是围岩变形规律及允许变形值等问题亟待解决。本文采用室内相似材料模拟实验、现场监测与综合分析、有限元分析及数值拟合分析等方法,研究连拱隧道由于开挖影响而引起的围岩水平位移和拱顶沉降等变形规律,建立了围岩变形的预测模型,推导出围岩水平位移和拱顶沉降等预测公式,并将其应用到类似条件的连拱隧道的工程设计、施工、安全管理及变形监测等工作中,直接指导连拱隧道工程建设。通过对连拱隧道变形监测数据的综合分析、实验研究和有限元理论分析,得到围岩位移变化的基本规律:在隧道宽度一定的条件下,围岩类型是引起位移值变化的主要因素,Ⅱ类围岩比Ⅲ类围岩引起的位移量大;施工方法不同,围岩位移的大小和分布不同,中导洞法施工引起的位移量最小,三导洞法引起的位移量较大;施工过程引起的最大径向位移发生在拱顶部分,其次为腰部和边墙,中墙处位移最小,所以在实际施工中应加强拱顶位移的监测与控制。在对连拱隧道大量监测数据及室内实验数据进行数值分析和统计分析的基础上,结合有限元理论的动态位移分析方法,分析得到连拱隧道Ⅱ类、Ⅲ类围岩条件下拱顶沉降和水平位移的允许变形值;并且,对类似条件连拱隧道施工过程的围岩位移进行了预测,结果令人满意。采用相似材料模拟实验方法成功地模拟了三导洞、双导洞和中导洞拓展法施工引起的Ⅱ类、Ⅲ类围岩位移变化情况,对位移的大小和分布规律进行比较分析后得到:中导洞拓展法施工引起的围岩位移小且施工方法简单,该施工方法是一种值得推荐的新方法。这样,为目前我国在Ⅱ类围岩中修建连拱隧道采用的方法增加了比选方案。通过有限元数值分析研究和变形监测得到:连拱隧道在整个施工过程中,出现4个较大变形量的集中区域,即边墙底部变形区、中墙底部变形区、中墙顶部变形区及左右两洞的边墙部位变形区。这4个集中变形区的围岩变形对整个隧道的稳定有着重大影响,必须加强监测并采取控制措施限制其变形量。设计并开发了连拱隧道变形监测数据处理与变形预测软件(BTDMCS),并已应用于实际工程,对施工过程进行实时动态数据处理与变形预测,能够为连拱隧道安全施工提供科学的辅助决策依据。更多还原

【Abstract】 The construction of highway in China is in a fast development period recently. Because of being limited by topographical and geological condition, a lot of double-arch tunnels are elected to pass through the mountains in the Mid-west. The stability of double-arch tunnel is a hotspot issue now because of its big span and complicated structure. Especially the law and allowable range of surrounding rock displacement remain to be studied deeply on.This paper adopts experiments simulated by equivalent materials, field monitoring measurement and finite element analysis method to study on deformation law of horizontal displacement and subsidence at top of double-arch tunnel caused by excavating. Some predicting models and calculating formulas on the displacement of surrounding rock are obtained, and then applied to design and construct projects, keep safe, monitor deformation, administer construction of similar double-arch tunnel and direct practical engineering.Though similar material imitating experiment, field monitoring measurement and finite element numerical analysis, the law of deformation of surrounding rock is got. With equal tunnel width, the type of surrounding rock is the important factoy changing deformation. Distancement in typeⅡrock is much more than typeⅢrock; different methods of tunnel construction make values and distribution of displacement differently. The displacement caused by middle-pilot method construction is less while the displacement caused by three-pilot method is more; the biggest radial displacement is at the top of arch in construction process, next came at the waist and the sidewall, the smallest is at the middlewall. Therefore, the monitoring and prevention of displacement at the top of arch should be strengthened in the construction.Based on the numerical analysis and statistical analysis through massive monitor data of double-arch tunnel and the laboratory test data, and combined with finite element theory dynamic analysis, the critical deformation values of the arch top subsidence and horizontal displacement are obtained under the typeⅡand typeⅢsurrounding rock condition. At the same time, the displacement forecast is carried on to the similar tunnel construction process and obtains good results.The similar material imitating experiment has successfully simulated the changing displacement which caused by methods of three-pilot holes, double-pilot hole and middle-hole excavation in the typeⅡand typeⅢsurrounding rock. The sizes and distribution rules of displacement are compared and conclusion is obtained: the method of middle-hole construction is simple and the surrounding rock displacement caused by it is small, therefore it is a kind of new method which is worth recommending. Thus a new method is added for construction of double-arch tunnel in the type II surrounding rock.According to the analysis of finite element method and to data of deformation monitoring measure, four concentration areas of deformation appear in the construction of double-arch tunnel ,which are at bottom of side-wall, at bottom of middle-wall, at top of middle-wall and at side of side-wall of two holes. The rock deformation is important for stability of double-arch tunnel, so the monitoring, measurement and adopts steps of it must be strenthened to control deformation of surrounding rock.This paper desigs and develops Bi-Tunnel Deformation Monitor Computer System(BTDMCS) which has been applied actually in some bi-tunnel engineering to monitor deformation. Dynamic predicting managment is carried out. The correctness and serviceability of the soft are tested and verified.更多还原