深埋隧（巷）道围岩变形破裂研究

发布时间：2018-01-31 13:45

本文关键词： 深埋隧道开挖卸荷分区破裂数值模拟变形破裂规律　出处：《中国矿业大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着矿山开采等地下工程深度的增加,处于高围压和复杂地质环境中的隧道围岩在开挖过程中出现复杂的变形现象,深部隧(巷)道开挖造成的围岩变形破裂逐渐引起广泛的关注和重视,并成为近年来岩石力学学科的研究热点。本论文以深部隧道为研究对象,采用理论分析、数值模拟等方法对隧道开挖围岩的变形破裂规律进行研究,研究内容及成果主要包括:(1)对于深埋圆形隧道开挖问题,将围岩开挖视为动态变化过程,在理论分析中将隧道开挖扰动问题分解为隧洞周边受力和隧洞外边界受力两个子问题;用二次抛物线函数曲线来模拟隧道开挖卸荷随时间的变化过程,采用Laplace积分变换求出隧道开挖受载,再运用Den Iseger法进行Laplace逆变换的数值计算,将两个分解问题的计算解叠加以此获得圆形隧道动态开挖问题的解析解,从而得到深埋隧道开挖过程中应力和变形随时间的变化规律;然后再从静态力学的角度进行弹性和弹塑性力学分析,得到隧道开挖的静态解析解;最后通过动静态力学解析结果的对比得出深部隧道开挖动静态解的差异性。(2)针对深埋圆形隧道开挖问题出现的分区破裂现象,建立从内向外依次为破裂区-弹性区-破裂区-弹性区的分区破裂力学分析模型,采用Mohr-Coulomb准则进行非关联弹塑性分析,获得各个分区围岩应力和变形的理论解析解,并根据围岩不同分区的边界条件以及围岩应力和变形的存在状态推导分区破裂的形成条件。(3)对深埋隧道的开挖进行数值模拟分析,首先研究隧道埋深、侧压系数、最大水平主应力与隧道轴向不同夹角等单因素作用下直墙拱隧道开挖后围岩的应力及变形规律。其次,考虑圆形隧道的开挖卸荷效应,基于围岩的物理力学参数随开挖过程不断变化的条件研究不同侧压系数对开挖完成后围岩的应力和破坏规律以及不同初始地应力大小对开挖卸荷过程中围岩应力和变形的影响规律,为隧道的稳定性分析和支护设计提供理论依据。
[Abstract]:With the increase of the depth of underground engineering such as mining, the surrounding rock of tunnel in the high confining pressure and complex geological environment appears complex deformation phenomenon in the course of excavation. The deformation and fracture of surrounding rock caused by excavation of deep tunnel (roadway) has gradually aroused widespread concern and attention, and has become the research hotspot of rock mechanics in recent years. This paper takes deep tunnel as the research object and adopts theoretical analysis. Numerical simulation and other methods are used to study the deformation and fracture law of surrounding rock in tunnel excavation. The research contents and results mainly include: (1) for the excavation of deep buried circular tunnel, the excavation of surrounding rock is regarded as a dynamic change process. In the theoretical analysis, the disturbance problem of tunnel excavation is decomposed into two sub-problems: the surrounding force of the tunnel and the external boundary force of the tunnel. The quadratic parabola function curve is used to simulate the unloading process of tunnel excavation with time, and the load of tunnel excavation is obtained by Laplace integral transformation. Then the Den Iseger method is used to calculate the inverse Laplace transform, and the solution of the two decomposition problems is superposed to obtain the analytical solution of the dynamic excavation problem of circular tunnel. Thus, the variation of stress and deformation with time during the excavation of deep buried tunnel is obtained. Then elastic and elastoplastic mechanics are analyzed from the angle of static mechanics, and the static analytical solution of tunnel excavation is obtained. Finally, through the comparison of dynamic and static mechanical analysis results, the difference of dynamic and static solutions of deep tunnel excavation is obtained. A fracture mechanics analysis model with the order of rupture zone, elastic zone, rupture zone and elastic zone from inward to outer is established, and the Mohr-Coulomb criterion is used to analyze non-correlation elastic-plastic analysis. The theoretical analytical solutions of stress and deformation of surrounding rock in each zone are obtained. And according to the boundary conditions of different zones of surrounding rock and the stress and deformation of surrounding rock, the formation condition of zonal fracture is deduced. The excavation of deep buried tunnel is analyzed numerically. First, the depth of tunnel is studied. The lateral pressure coefficient, maximum horizontal principal stress and different axial angle of tunnel, etc., under the action of single factor, the stress and deformation of surrounding rock after excavation of straight wall arch tunnel are considered. Secondly, the excavation unloading effect of circular tunnel is considered. Study on the changing condition of the physical and mechanical parameters of surrounding rock with the excavation process; the stress and failure law of surrounding rock after excavation with different lateral pressure coefficient and the stress of surrounding rock during excavation unloading with different initial in-situ stress. And the influence of deformation. It provides a theoretical basis for the stability analysis and support design of the tunnel.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U451.2

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