【作者】 郭子红；

【导师】 刘新荣；

【作者基本信息】 重庆大学 ， 土木工程， 2010， 博士

【摘要】 随着社会经济高速发展和城市化高度集中,地面建筑和交通等设施已经不能满足社会发展的需要,对地下空间的开发与利用已成为当今城市建设的焦点。地铁隧道和公路隧道的修建是地下空间开发最为常见的形式之一,为满足地形和线路的要求,近接隧道的设计与施工层出不穷。以拟建重庆朝天门两江隧道中出现的近接隧道为研究背景,采用理论分析、模型试验和数值分析等方法对近接隧道的稳定性进行了较为深入的研究,主要研究内容与结论如下:(1)采用极限平衡原理与变分方法共同分析浅埋隧道的最不利滑裂面分布,定义最不利滑裂面上的抗滑力与下滑力之比为浅埋隧道安全系数。基于浅埋隧道稳定性分析方法,并结合浅埋近接隧道失稳的多种模式,研究了浅埋近接隧道的多安全系数稳定性分析方法。(2)根据破坏角与主应力的关系获得深埋独立圆形隧道围岩内部滑裂面的分布,采用变分方法对隧道围岩滑裂面的分布进行验证;将围岩简化为理想弹塑性材料,以隧道滑裂面和极限塑性区半径为基础,定义滑裂面上平均抗剪强度与平均剪切应力之比为深埋隧道的安全系数。(3)根据对称性原理先将深埋并列近接隧道转换为含一个圆孔的半无限平面,从而将比较复杂的多连通域转换为双连通域。选用映射函数将含一个圆孔的半无限平面映射为同心圆环,采用弹性力学的复变函数方法求出深埋并列近接隧道的应力分布,据此进行深埋近接隧道稳定性分析。(4)采用公路隧道结构与围岩综合试验系统对交错近接隧道进行三维物理模型试验,研究了由新建隧道开挖引起既有隧道围岩内部压应力、围岩内部位移及支护结构内力的变化规律。(5)采用有限元软件ANSYS对交错近接隧道中新旧隧道相互影响进行模拟分析,将其结果与模型试验结果进行对比,验证了模型试验结果的合理性。对比分析不同开挖方案条件下的数值模拟结果,优化了交错近接隧道的开挖方案。(6)以浅埋近接隧道的稳定分析理论方法探讨了浅埋近接隧道的安全系数,以该安全系数为依据对隧道围岩的强度参数进行折减,采用数值模拟分析近接隧道的塑性区发展规律,据此对比验证浅埋近接隧道的稳定性与稳定分析方法的合理性。更多还原

【Abstract】 Due to the rapid development of social economy and urbanization that has occurred in China over the last few years, ground construction and transportation facilities have not been able to meet the needs of social development. Therefor, how to efficiently develop and utilize of urban underground space has attracted more and more attention from academic organizations and governments. Subway tunnels and road tunnel construction is one of the most common underground space development. In order to meet the terrain and the lines, many adjacent tunnel’s design and construction come forth endlessly. Planned Liang jiang tunnel at Chaotianmen in Chongqing serving as research background, stability of adjacent tunnel have been analyzed with theoretical analysis, numerical simulation and model test. The research contents and conclusion are as follows:(1) Based on the limit equilibrium theory and variation method, the most dangerous sliding surface of shallow tunnel is studied. The safety factor was defined as the ratio of anti-sliding force to sliding force on the most dangerous sliding surface. According to the instability mode and stability analysis methods of shallow adjacent tunnels, stability analysis method of shallow adjacent tunnel has been studied.(2) According to the relationship between rupture angle and principal stress, the distribution of failure surface in surrounding rock of deep circular tunnel was obtained, which was verified used the variation method. Surrounding rock have been simplified as elastic-perfectly plastic material, then based on sliding surface and critical plastic radius, The safety factor of deep circular tunnel was defined as the ratio of average shear strength to average shear stress on the sliding surface.(3) Deep parallel tunnel has been transformed into half plane with circular tunnel according to the symmetry principle, then multi-connected domain is turned into double connected domain. With mapping function half plane with circular tunnel is transformed into concentric annulus, then deep adjacent tunnel’s stress is solved with complex variable function method of elasticity mechanics. Based on the result, the deep adjacent tunnel stability can be judged.(4) On the base of the comprehensive testing system for structure and surrounding rock masses of highway tunnel(CTSSSRH), three-dimensional model test about forked tunnel with different altitude have been carried out. In order to analysis the new tunnel’s influence on the existing tunnel, the distributions and changes of surrounding rock pressure, surrounding rock internal displacement and internal force of support structure of the existing tunnel have been metered and analyzed.(5) With finite element software ANSYS, the interaction between old and new forked tunnel with different altitude have been analyzed. the results compared with model experimental results, witch shows that model experimental results are rational. Comparing the numerical simulation results under the condition of different excavation scheme, the reasonable excavation scheme has been studied.(6) The safety factor of shallow adjacent tunnel is calculated with stability analysis method of shallow adjacent tunnel. The strength parameters of surrounding rock are reduced according to these safety factors, then the numerical simulation is used to analyze of shallow adjacent tunnel’s plastic zone. The two methods are used to analyze and verify shallow adjacent tunnel’s stability.更多还原