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为了从根本上防治隧道底臌和仰拱破裂,针对挤压流动条件下隧道底板变形破坏规律研究的不足,通过建立隧道侧墙岩体在支承压力作用下的力学模型,分析了侧墙岩体和顶、底板界面应力以及岩体轴力的基本分布规律,推导了侧墙岩体水平收敛位移及其极限平衡区宽度的理论计算公式。在此基础上,进一步分析了隧道底板岩体在侧墙岩体的挤压下产生塑性流动时的最大剪切破坏深度及其与相应侧墙的距离。最后以云岭隧道底臌为工程实例,对隧道侧墙和底板的初期支护参数进行了优化设计。分析结果表明:底板最大破坏深度及其与隧道侧墙的距离取决于侧墙岩体的极限平衡区宽度和底板岩体的内摩擦角;对于挤压流动性底臌,在加强地下水封堵和提高仰拱抗变形能力的同时,更应注重对隧道侧墙和底板岩体的锚注联合初期支护,为后续挤压流动性隧道底臌灾害的有效防治提供参考。
In order to fundamentally prevent and control the tunnel bottom and sublet arch rupture, in view of the lack of research on the deformation and failure of the tunnel floor under the conditions of squeezed flow, by establishing the mechanical model of the tunnel side wall rock mass under the bearing pressure, the side wall rock mass And the top and bottom interface stress as well as the basic distribution law of rock mass axial force, the theoretical calculation formula of horizontal convergence and displacement of side wall rock mass and the width of the limit equilibrium area is deduced. On this basis, the maximum shear failure depth and its distance to the corresponding side wall when the plastic deformation of the tunnel floor rock is squeezed by the side wall rock mass are further analyzed. Finally, taking the bottom of Yunling tunnel as an example, the initial support parameters of sidewall and floor of tunnel are optimized. The results show that the maximum failure depth of the bottom plate and its distance from the side wall of the tunnel depend on the width of the limit equilibrium zone of the side wall rock mass and the internal friction angle of the bottom plate. For the squeezed flow bottom, At the same time, it is necessary to pay more attention to the initial support of anchor and grouting joint for side wall and bottom rock mass of tunnel, which can provide references for the effective prevention and control of the bottom 臌 disaster of squeezed flow tunnel.