深部大变形巷道围岩破坏与稳定性控制研究

The deformation and failure of surrounding rock with large deformation in deep roadway is the result of formation and development of plastic zone; and deep expansion of boundary the malignant expansion of plastic zone is the immediate cause of large deformation and loosening damage of surrounding rock, and failure of supporting. It is made a breakthrough for the usual field test, a series of new independent techniques including the capacitive bar precision measuring instrument; the drilling cruise recording instrument and the roof collapse hidden danger detecting instrument are adopted. Combining with comprehensive research method of different levels and multiple subjects, the formation and development of plastic zone and the deep expansion of boundary be taken as the mean line, the physical structure characteristics and rock mechanics behavior of deep rock mass, the formation mechanism of plastic zone, the geometric distribution characteristics and time-spatial revolution evolution of plastic zone boundary will be studied. The failure mechanism of surrounding rock and supporting causing by the malignant expansion of plastic zone be revealed, the stability criterion of surrounding rock with large deformation in deep roadway will be established, and stability control principle of surrounding rock will be put forward based on which can prevent the plastic zone development from steady state to unsteady state, and keep down the malignant expansion of plastic zone. New techniques including long bolt and elastic cable of proprietary intellectual property rights are taken as the lead content, research and application of field will be made according to the principles of surrounding rock reinforcement and stress control. These researches can provide theoretical basis and new technical way for the stability control of surrounding rock with large deformation in deep roadway.

深部大变形巷道围岩变形破坏是围岩塑性区形成、发展及边界蠕变扩张的结果，塑性区的恶性扩展是围岩产生大变形、松动破坏和支护失效的直接原因。本项目突破传统的现场测试手段，采用容栅精密定位测量仪、钻孔巡航摄录仪、冒顶隐患探测仪等一系列自主研发的新技术，结合多层次跨学科的综合研究方法，以围岩塑性区的形成、发展及边界蠕变扩张为主线，研究深部岩体的物理结构特性与岩石力学行为、深部大变形巷道围岩塑性区形成机理、塑性区边界几何分布状态特征及时空演化规律；揭示巷道塑性区恶性扩展导致围岩破坏和支护失效的力学机制，建立深部大变形巷道围岩稳定性判别准则，提出基于防止巷道围岩塑性区由稳态向非稳态转化、遏制塑性区恶性扩展的巷道围岩稳定性控制原理；以具有自主知识产权的超长锚杆、弹性锚索等新技术为主导，结合围岩强化与应力控制，进行现场应用研究；为深部大变形巷道围岩稳定性控制提供理论依据和新的技术途径。

围岩大变形严重影响深部巷道的正常使用，其稳定性控制一直是岩石力学和采矿界的世界性难题。为解决这一难题，本项目以深部巷道围岩塑性区演化过程为主线，研究了大变形巷道围岩塑性区形成机理，揭示了塑性区扩展导致巷道围岩破坏和支护失效的力学机制，构建了巷道冒顶隐患指标体系和分级方法，研发了巷道锚杆（索）支护设计系统，实现了巷道冒顶隐患可视化分析和差异化设计，形成了巷道围岩控制技术体系。取得以下研究成果：. （1）开展了岩体加卸载与细观损伤试验，发现岩体强度、破坏形态、损伤程度及塑性变形均与其加载历史水平密切相关，应力水平越高，卸载后的岩体强度越小，塑性变形量越大，宏观与细观裂隙数量越多，岩体的损伤程度越加严重。. （2）建立了非等压环境下的巷道围岩力学模型，阐明了巷道围岩塑性区具有圆形、椭圆形和蝶形的三种基本形态，给出了塑性区三种基本形态的数学界定标准和应力围岩判别准则。. （3）分析了高偏应力环境下的巷道围岩塑性区演化过程，揭示了蝶叶型冒顶力学本质，获得了应力偏量大小、围岩强度、巷道尺寸以及蝶叶方位角等蝶叶型冒顶的关键影响因素。构建了巷道冒顶隐患多参量评估指标体系，建立了冒顶隐患判别准则，获得了巷道不同地段的冒顶隐患级别。. （4）建立了岩石性质与钻进信号特征的关联模型，研发了冒顶隐患探测仪、超高强柔性锚杆以及大延伸柔性锚杆，实现了大变形巷道冒顶隐患的精确定位，形成了大变形巷道围岩控制技术体系。. （5）基于蝶形破坏理论及其突变特性，揭示了巷道围岩塑性区恶性扩张引发冲击地压机理。. （6）研制了三轴加载试验装置，分析了锚杆支护强度、支护密度以及预紧力对预裂试件的锚固特征，构建了锚杆支护的劈裂板梁结构模型，揭示了深部巷道围岩锚杆锚固机理。. 本项目研究成果已在神华集团、潞安集团、冀中能源、湖南煤业等全国多个大型煤炭集团进行了推广应用，消除了冒顶安全隐患，降低支护成本，改善了支护效果，取得了显著的经济社会效益。