隧道支护与围岩作用体系的力学特性研究

发布时间：2018-03-16 22:03

本文选题：扰动效应　切入点：干预效应　出处：《北京交通大学》2017年博士论文　论文类型：学位论文

【摘要】：近年以来,我国城市轨道交通、高速铁路、高速公路等交通基础设施进入了大规模建设期,作为交通工程的重要载体,隧道工程的建设数量大幅增加、施工难题层出不穷,隧道设计理论已经明显滞后于工程实践。对支护与围岩作用体系的力学特点的认识深度直接决定了隧道工程设计和施工的科学性、安全性及经济性。因此,论文采用数值模拟、理论分析、室内试验和统计分析方法对开挖扰动下围岩变形的时空演化规律、隧道围岩力学响应的三维理论分析方法和支护结构体系与围岩相互作用的力学机理进行了深入研究,阐明了隧道支护与围岩作用体系的力学演化过程及其基本特点,建立了一种新的支护结构刚度确定方法。主要的研究成果包括:(1)隧道开挖扰动效应是支护与围岩作用体系力学演化的根本动力,无论地层结构特性和围岩物理力学参数如何变化,围岩变形均会经历"变形加速→急剧变形→缓慢变形→变形稳定"的四个阶段,且隧道洞周围岩变形的演化过程具有显著的自相似特性,这是由隧道开挖效应叠加的周期特性决定的。隧道拱顶围岩变形是判断围岩安全状态的基准指标,通过对侧压力系数为1的围岩变形结果的拟合分析得到了隧道拱顶围岩纵向变形曲线的计算公式。(2)将地层视为无限大或半无限大弹性体,以释放应力模拟隧道的开挖效应,分别建立深埋和浅埋圆形隧道围岩力学响应的三维分析模型,基于Mindlin解推导了围岩应力和位移的积分计算公式,编制相应的计算程序,通过与数值模拟结果的对比验证了其正确性,并分析了掌子面应力释放和洞壁应力释放对不同位置围岩径向位移和轴向位移影响的大小和范围。(3)提出广义和狭义隧道结构体系的概念,阐明各类支护结构的干预效应及其在隧道施工力学演化过程中的核心作用。初期支护是围岩荷载的主要承载结构,应用了高强钢筋的格栅混凝土复合支护结构具有高强度和大变形的力学特性,尤其适用于特殊地质和软弱围岩隧道。在扰动效应和干预效应的共同作用下,围岩变形演化仍呈现出四阶段特性。(4)基于对围岩变形演化规律和支护-围岩相互作用力学机理的研究,结合对大量隧道监测数据的统计结果,凝练出隧道支护与围岩动态作用过程的基本特点,然后基于一致性、普适性和典型性的原则将隧道掌子面、初期支护施作和二次衬砌施作确定为三个关键节点,并将隧道支护与围岩的动态作用过程划分为四个典型阶段,分别阐述各个阶段的作用特点、关键问题和控制要点。(5)基于隧道支护与围岩相互作用的基本特点和围岩力学响应分析的三维力学模型,从隧道围岩的支护需求出发,建立了一种新的支护结构刚度确定方法。基于实际工程对易用性的要求,编制了包含各分析步骤重要参数的支护结构快速设计参考表。该方法具有便捷性、开放性的特点,其计算精度将随理论研究的深入和计算技术的进步而不断提高。
[Abstract]:In recent years, our country city rail transportation, high-speed railway, highway and other transportation infrastructure in the large-scale construction period, as an important carrier of traffic engineering, tunnel engineering construction quantity increase, the construction problems of the tunnel design theory has been emerge in an endless stream, lagged behind the engineering practice. The depth of understanding mechanical characteristics of surrounding rock and support system directly determines the scientific tunnel engineering design and construction, safety and economy. Therefore, using numerical simulation, theoretical analysis, laboratory tests and statistical analysis on the temporal and spatial evolution of the excavation disturbance of surrounding rock deformation, three-dimensional theoretical mechanics response analysis method of tunnel surrounding rock and supporting structure and surrounding rock interaction system the mechanical mechanism is studied, the tunnel surrounding rock mechanics and the system evolution and its basic characteristics, establish A new method to determine the stiffness of the support structure. The main results include: (1) the tunnel excavation disturbance effect is the fundamental motive force supporting system evolution and rock mechanics, no matter how the structural characteristics of strata and rock mechanics parameters, the deformation of surrounding rock are four stages "to accelerate the deformation history the sharp deformation and slow deformation, deformation and stability", and the evolution process of rock around tunnel deformation has obvious self similarity, which is decided by the cycle characteristics of tunnel excavation effect. The tunnel surrounding rock deformation is to determine the benchmark security status of the surrounding rock, the calculation formula of lateral pressure coefficient for fitting analysis the results obtained with the surrounding rock deformation of 1 Tunnel Surrounding Rock longitudinal deformation curve. (2) the apparent formation is infinite or semi infinite elastic body, to release the stress simulation of tunnel excavation effect, respectively. The 3D analysis model of deep and shallow buried circular tunnel surrounding rock mechanics response, Mindlin analytical solutions of surrounding rock stress and displacement integral formula based on the corresponding program is compiled, by comparing with the numerical simulation results verify its correctness, and analyzes the face stress release and wall stress release size the influence of different position of the radial displacement and axial displacement of surrounding rock and range. (3) proposed the concept of broad and narrow tunnel structure, the core effect of the intervention to elucidate the role of supporting structure in tunnel construction mechanics and its evolution process. The initial support is the main bearing structure of surrounding rock load, the application of high strength steel grille concrete composite supporting structure with high strength and large deformation of the mechanical properties, especially suitable for the special geological and soft rock tunnel. In the action of disturbance effect and intervention effect of the, The surrounding rock deformation evolution still shows the characteristics of four stages. (4) the deformation evolution and support rock interaction mechanism research on surrounding rock based on the combination of statistical results of a large number of tunnel monitoring data, summarizes basic characteristics of tunnel support and surrounding rock dynamic process, and then based on consistency, universality and the typical principle of tunnel face, initial support and the two lining is determined as three key nodes, and divides the dynamic effect of tunnel supporting and surrounding rock process for four typical stages, respectively on the characteristics of each stage, and the key control points. (5) three dimensional mechanics the model response analysis of tunnel support and surrounding rock and rock mechanics based on basic characteristics, starting from the tunnel surrounding rock support needs to establish a new method to determine the stiffness of the support structure. Based on the actual engineering for ease of use According to the requirement of sex, a reference table for rapid design of supporting structures, which contains important parameters of all the analysis steps, has been compiled. This method is characterized by convenience and openness, and its calculation accuracy will continue to improve with the deepening of theoretical research and the progress of computing technology.

【学位授予单位】：北京交通大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：U451

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