基于软弱破碎围岩锚注力学特性的深部巷道控制机理研究

Bolt-grouting support is an effective means to solve the control problem of weak and fractured surrounding rock in deep roadway, but its mechanical characteristics and control mechanism are still unclear, which leads theory lagging behind practice, and restricts the development of this technology. . This project takes typical weak and fractured surrounding rock roadway as engineering background. The interfacial shear test of anchor-grouting is carried out to study the correlation between the damage evolution of interfacial morphology and grouting parameters, lithology, rock fragmentation and stress level. A reasonable damage factor is proposed and the coupling effect between the damage factor and the interface stress and displacement is analyzed based on the normalization idea and the non-linear description, and the criterion of shear strength of the anchor-grouting interface is established. Combined with the test of bearing characteristics of bolt-grouting body, the crack development law and failure characteristics of bolt-grouting body are analyzed, the whole course relationship between bolt-grouting support and surrounding rock deformation is clarified, and the theoretical model of bolt-grouting bearing capacity and the prediction model of surrounding rock deformation are constructed. Then the field comparative test of bolt-grouting control is systematically carried out to study the time-varying law of bolt-grouting bearing capacity and the law of grouting diffusion reinforcement, and to reveal the control mechanism of bolt-grouting in weak and fractured surrounding rock of deep roadway. The research results can provide theoretical basis and technical guidance for bolt-grouting support of deep roadway.

锚注支护是解决深部巷道软弱破碎围岩控制难题的有效手段，但是其力学特性及控制机理仍不明确，导致理论滞后于实践，制约了该技术的发展。. 本项目拟以典型软弱破碎围岩巷道为工程背景，开展锚注界面剪切试验，研究界面形态损伤演化与注浆参数、岩性、岩体破碎程度以及应力水平的相关性，基于归一化思想和非线性描述，提出合理的强度损伤因子并分析与界面应力、位移之间的耦合效应，建立锚注界面抗剪强度判据。结合锚注体承载特性试验，分析锚注体裂纹发展规律和破坏特征，明确锚注支护与围岩变形全历程关系，构建锚注承载力学模型和围岩变形预测模型。在此基础上，系统开展锚注控制现场对比试验，研究锚注承载时变规律与浆液扩散加固规律，揭示深部巷道软弱破碎围岩锚注控制机理。研究成果可为深部巷道锚注支护提供理论依据和技术指导。

本项目以巨野矿区千米深井-赵楼煤矿为工程背景，针对深部软弱破碎围岩巷道控制难题，采用理论分析、室内试验、数值试验以及现场试验相结合的研究方法，进行深部巷道软弱破碎围岩锚注力学特性及控制机理研究。. 项目主要对通过深部软弱破碎围岩变形破坏开展了现场监测，得到了赵楼煤矿深部软弱破碎围岩变形破坏的主要问题及破坏机制。考虑锚固体界面剪胀效应，推导了注浆前后锚注界面抗剪强度判据，讨论了围岩弹性模量、粘聚力、内摩擦角、剪胀角对锚固体界面抗剪能力的影响规律；根据Hoek-Brown强度准则及其相关联流动法则，推导了硐室圆弧平顶稳定曲线方程，分析了岩体单轴抗压强度、围岩应力、支护阻力以及平顶高度等参数对圆弧平顶稳定性的影响规律。采用自主研发的破碎岩体注浆加固装置，开展了不同粒径、不同水灰比条件试件变形破坏以及相应的能量变化特征研究，分析了试件主要力学参数之间的关系；开展了不同岩体粒径、不同水灰比、不同杆体数量的软弱围岩锚注体压缩试验，对比分析了不同因素影响下锚注体承载特性。开展了注浆锚索锚固性能试验，对比分析了不同岩体粒径、不同水灰比条件下注浆锚索拉拔过程中应力、位移变化规律，以及注浆锚索失效特征，得到了注浆锚索剪应力-位移全历程曲线。开展了不同长度注浆锚杆浆液扩散性能拉拔试验和注浆锚索支护参数现场测试，比选了合适的注浆锚杆长度、注浆锚索长度以及间排距等锚注参数。设计了无支护、锚网喷支护和锚注支护三大类支护方案，分析了不同支护方案下巷道位移、塑性区以及应力演化特征，明确了不同支护方案下围岩变形破坏机制。选取赵楼煤矿2#联络巷、七采辅运巷为试验对象，开展了现场锚注控制效果对比试验。通过理论分析、室内试验、数值试验以及现场试验综合研究，最终得到了深部巷道软弱破碎围岩锚注力学特性及控制机理。