【作者】 陈志强；

【导师】 周科平；

【作者基本信息】 中南大学 ， 地下空间科学与工程， 2010， 硕士

【摘要】 随着我国交通事业的迅速发展和城市化进程的不断推进,地下工程在公路、铁路和市政建设等领域得到了空前的发展,不论是数量还是规模都是巨大的。隧道工程作为最普遍的一种地下工程,其建设的数量也会日益增多,目前现有的隧道支护结构的设计方法难以兼顾断面的合理性和支护结构的承载力和稳定性。本文用可靠度来分析结构的稳定性,使隧道工程设计更加合理、科学,更能反映问题的实质。本文以连霍高速甘肃省内某分离式公路隧道为研究对象,针对隧道施工过程中的力学响应和隧道结构可靠度进行了系统的研究。本文的主要研究内容如下：(1)采用FLAC3D数值模拟的手段,对隧道施工过程进行数值模拟。结合岩土材料的非线性特性,阐述了隧道施工过程的数值计算理论和模拟方法。根据FLAC3D建模技术,通过确定物理力学参数、初始条件、边界条件、材料的本构关系、单元网格类型等,建立隧道的平面几何模型,并对同步开挖和异步开挖两种隧道施工过程和全断面法和台阶法两种施工方法进行了数值模拟,得出了不同工况下的应力、应变、位移场的分布规律；(2)分析围岩体与支护结构的稳定性问题,并根据围岩与支护结构共同作用的机理,阐述了隧道结构整体稳定性的相关问题,引出隧道结构可靠度的问题;(3)以工程实例为依托,根据隧道结构的极限状态方程,采用Monte Carlo法编程计算隧道结构的可靠度；应用神经网络的特性,通过编程,计算隧道结构可靠度。两相对比,证明基于神经网络的结构可靠度计算方法确实可行。更多还原

【Abstract】 With the rapid development of China’s transport sector, and the process of urbanization continuously pushed forward, underground construction in roads, railways and municipal construction in areas makes an unprecedented development, both in number and scale. Tunnel, as the most pervasive form of underground works, the number of its construction will also be increasing.The current methods of the existing tunnel support structure design is difficult to take into account a reasonable cross-section support structure and the bearing capacity and stability. In this paper, the structural reliability was applied to analyze the stability of tunnel engineering and make the design more rational, scientific, better reflect the essence of the problem.In this paper, take a separated highway tunnels as an example, which is in Gansu sector of Lianyungang-Huoerguosi speedway, the mechanical response in the tunnel construction process and reliability of the tunnel structure was systematically studied. Main contents of this article are as follows:(1) By the means of numerical modeling based on FLAC3D, tunnel construction process is simulated. According to the non-linear characteristics of geotechnical materials, the process of tunnel construction theory and numerical simulation methods are explained. Based on the FLAC3D modeling techniques and determination of the physical and mechanical parameters, initial conditions, boundary conditions, material constitutive, cell type of the grid, the plane geometry model of the tunnel was established. Two kinds of tunnel excavation construction process as synchronous excavation and asynchronous excavation were modeling by numerical simulation method, obtaining the distribution law of stress, strain and displacement under different conditions of construction;(2) Analysis on the stability problems of surrounding rock mass and supporting structure was carried. According to the interaction mechanism between the supporting structure and surrounding rock, the overall stability of the tunnel structure was studied. The reliability problems on structure were presented.(3) Taking the tunnels as the study subject and according to the ultimate limit states tunnel structure, the Monte Carlo method is used to calculate the reliability index; On account of the features of artificial neural network, try to compute the reliability index by programming in artificial neural network. By comparison of two methods, it proved that the structural reliability based on neural network method is indeed feasible.更多还原