深部破裂围岩与自适应支护结构耦合作用机制

At present, mechanical behavior and instability mechanism of crushed surrounding rock mass have so far not been revealed clearly, which has become the major problems restricted stability control of surrounding rock of deep roadway. Thus, in this project, deep crushed rock mass is taken as the research object. First, experimental study on macro and microscopic mechanical properties of crushed rock mass will be carried out, from which, the strength degradation, dilatancy properties, re-failure behavior of broken rock under loading and unloading conditions can be revealed. Relationship between the rupture degree of the surrounding rock and its strength can be established, and a damage dilatancy - broken expansion constitutive model which reflects the mechanism of large deformation and instability can be established. Then, dynamic evolution laws of both stress field and displacement field of surrounding rock under the roadway excavation and supporting will be obtained by conducting large three - dimensional similar material model tests and adopting the stereo optical fiber digital test measurement and control system. Combined with fissures detection results of the surrounding rock using the panoramic borehole digital camera, and the three - dimensional finite element - discrete element coupled numerical simulation analysis technique, fracture evolution process and the instability mechanism of the surrounding rock can be analyzed. Finally, the anchorage structure of stepwise constant resistance and shear resistance with large deformation will be developed, and coupling model of the surrounding rock and the supporting structure will be established, from which, the response characteristics and the interaction of the surrounding rock and the supporting structure will be revealed. The research results can provide theoretical foundation for the stability control of deep roadway surrounding rock, and are of great significance in deep resources exploitation in China.

目前破裂围岩的力学行为与失稳机理尚未清楚，已成为制约深部巷道围岩稳定控制的突出难题。本项目以深部破裂围岩为研究对象，首先开展破裂岩石宏细观力学特性试验，揭示加卸载条件下破裂岩石的强度劣化、扩容特性及再破坏行为，建立围岩破裂度与其强度间的内在关系，构建可反映深部破裂围岩大变形失稳机理的损伤扩容-破裂碎胀本构模型。然后，采用大型三维相似材料模型试验与立体声测光纤数字测试系统，揭示巷道开挖与支护条件下围岩应力场和位移场的时空演化规律；并结合全景钻孔数字摄像仪对围岩裂隙的探测结果和三维有限元-离散元耦合数值模拟分析技术，分析深部巷道围岩破裂演化过程与失稳机理。最后，研制对深部巷道围岩大变形具有自适应性的分级恒阻抗剪大变形锚固结构，建立巷道围岩-支护结构耦合作用力学模型，揭示围岩与支护结构的响应特征及相互作用规律。研究成果可为解决深部巷道围岩稳定控制难题提供理论基础，对我国深部资源开采具有重要意义。

开发深地资源已经成为未来我国科技发展的重要方向，深部资源开采过程中所产生的岩石力学问题已成为国内外研究的热点。目前对破裂围岩力学行为与失稳机理的认识尚未清楚，已成为制约深部巷道围岩稳定控制的突出难题。本项目围绕深部破裂围岩再破坏后的强度与变形及碎胀扩容特性、深部破裂围岩应力场和位移场演化规律及围岩-支护结构相互作用机制等2个关键科学问题，开展了深部破裂围岩结构演化特性与再破坏力学行为试验、深部破裂围岩损伤扩容-破裂碎胀大变形本构模型、深部巷道破裂围岩时空演化规律与失稳机理试验、深部巷道破裂围岩与自适应支护结构耦合作用机制等4个方面的研究内容。首先，提出了采用同步卸除轴压与围压的三轴卸荷试验来制备损伤和破裂岩样的试验方法，建立了适用于描述岩石损伤破裂行为的表观损伤破裂变量，开展了岩样破裂后再破坏的再承载试验，揭示了不同破裂度岩样的强度与变形特性、扩容特性的演化规律。然后，建立了描述岩石损伤、屈服和破坏演化过程的临界强度准则，构建了基于破裂度的反映深部破裂围岩大变形失稳机理的损伤扩容-破裂碎胀本构模型，分析了深部破裂围岩渐进破坏的过程与大变形失稳力学机理。其次，搭建了围岩变形-应力综合测试系统，获得了三维相似模型试验中巷道围岩变形和应力及支护结构受力状态；结合岩石损伤扩容-破裂碎胀大变形本构模型的二次开发与数值模拟方法，基于安全系数法定量评价了围岩稳定状态，分析了深部巷道围岩破裂演化过程与破坏模式。最后，研制了对深部巷道围岩大变形具有自适应性的分级恒阻抗剪大变形锚固结构，分析了其在拉伸、剪切等条件下的力学与变形特性；建立了围岩-支护结构耦合作用力学模型，获得了围岩应力和位移及支护结构响应的半解析解；开发了可模拟分级恒阻特性的新型锚索单元模型，揭示了围岩与支护结构的响应特征及耦合变形控制效应。研究成果可为解决深部巷道围岩稳定控制难题提供理论基础，对我国深部资源开采具有重要意义。