深部隧道碎裂围岩大变形演化特征及锚喷支护作用机理研究

In deep tunnels, fragmentation of the rock mass and repeatedly fractured surrounding rock mass will be produced after excavation, which will cause the large deformation and interval disintegration. Serious engineering accidents occur easily if the large deformation and interval disintegration can not be controlled effectively, bringing great economic loss and unnecessary casualties to engineering project. In order to solve these problems, the failure mechanism, evolution law and characteristics of large deformation under construction disturbance in deep tunnels will be studied systematically through model test. The evolution equation of large deformation and the catastrophe model for fragmentation surrounding rock mass under construction disturbance will be established .This research will analyze the development law and control factors for repeatedly fractured surrounding rock under construction disturbance, proposing technology and methods of flexible bolt-shotcrete support which can effectively control large deformation of surrounding rock in deep tunnels. The characteristics of large deformation and mechanism of bolt-shotcrete support will be revealed. Based on manifold cover system, we will establish the numerical analysis method for large deformation in fragmentation rock mass and mechanical model of bolt-shotcrete support. The study results can provide theoretical and technical support for prevention and analysis of engineering disaster problems, such as massive collapse and interval disintegration caused by large deformation of fragmentation rock mass under construction disturbance in deep tunnels.

深部隧道开挖后，在隧道围岩中会产生许多碎裂岩体和不断向纵深发展的反复破裂围岩，这些碎裂岩体和围岩将引起隧道产生大变形及间隔破裂。如果大变形和间隔碎裂围岩得不到有效控制，将引起隧道产生大体积塌方等工程事故，给工程带来极大的经济损失和不必要的人员伤亡。为了解决这些问题，本研究以模型试验为手段，系统研究深埋隧道施工扰动下围岩变形破坏机理、间隔破裂围岩发展规律及其大变形演化特征，建立施工扰动下深部隧道碎裂围岩大变形演化方程及其诱发的大体积塌方临灾突变模型；分析施工扰动下反复碎裂围岩发展规律及其控制因素，提出有效控制深部隧道围岩大变形的柔性锚喷支护技术与方法，揭示碎裂围岩大变形特征及其锚喷支护作用机理，建立基于流形覆盖的离散单元法，形成适合碎裂围岩大变形和锚喷支护力学模型的数值分析方法。为深部隧道施工扰动下碎裂围岩大变形诱发的大体积塌方、间隔破裂等工程灾害问题的防治和分析提供理论基础和技术支撑。

深部资源开发中地下洞室围岩中会产生许多碎裂岩体，引起隧道产生大体积塌方等工程事故，给工程带来极大的经济损失和不必要的人员伤亡。因此本课题研究了开挖扰动下裂隙围岩碎裂机理，间隔破裂围岩发展规律及其大变形演化特征，开展了室内试验及大尺度裂隙岩体三维模型试验，分析了碎裂围岩非连续变形及其强度特性，揭示了碎裂围岩大变形特征及其锚喷支护作用机理.提出了施工扰动下诱发的碎裂围岩大变形演化方程及其大体积塌方突变模型和模拟碎裂围岩及其锚喷支护的数值分析方法——基于流形覆盖的离散单元法。同时结合大变形现场试验和实际工程，研究了不同类型喷射混凝土及其锚固形式对碎裂围岩大变形的影响规律，并改进了喷射混凝土工艺及其锚固形式，建立了一套较完整的深部围岩控制理论体系。为深部隧道施工扰动下碎裂围岩大变形诱发的大体积塌方、间隔破裂等工程灾害问题的防治和分析提供了理论基础和技术支撑。