动压巷道锚杆锚固结构失效机理及其健康诊断研究

The health diagnosis and failure mechanism of roadway bolt anchoring structure under dynamic pressure were studied with the methods such as theoretical analysis, experimental research, physical simulation, numerical simulation and field test. Based on the key strata theory, the deformation of overlying key stratain working face, rupture regularity and the characteristics of mining pressure load were researched, and the mechanical features of deformation surrounding rock of roadway under dynamic pressure were revealed under the static and dynamic state respectively; meanwhile, the static and dynamic damage mechanism of prestressed bolt anchoring structure was discussed under the effect of pressure of surrounding rock and dynamic disturbance, which was based on the fundamental principle of viscous -elastics -plastic mechanics, damage mechanics and kinetics. The damage anchoring load mode and the touch mechanisms of prestressed bolt anchoring structure were clarified, at the same time, the calculation basics of damage anchorage body load were raised and the failure criterion was put forward under prestressed bolt anchoring structure, which could establish theory basis for support design and the effect evaluation of the bolt support roadway under dynamic pressure. Based on the stress wave theory, the dynamic response law of prestressed anchor structure was studied under a certain damage condition, the health diagnosis principle was expounded under the prestressed bolt anchoring system state, and a kind of health diagnosis method was provided, which was based a dynamic detection of prestressed bolt anchoring structure, could offer measured basis for the evaluation of stability of bolt support surrounding rock of roadway.

采用理论分析、实验室试验、物理模拟、数值模拟和现场测试相结合的综合研究方法，进行动压巷道锚杆锚固结构失效机理及其健康诊断研究。基于关键层理论研究大采高和构造复杂条件回采工作面上覆关键层变形、破断规律和采动压力载荷特点，揭示动压巷道围岩变形的静、动态力学特征；基于粘-弹-塑性力学、损伤力学和动力学基本原理研究预应力锚杆锚固结构在围岩压力和动力扰动作用下静、动态损伤机理，阐明损伤锚固体承载模式和预应力锚杆锚固结构失效的触动机制，并提出损伤锚固体承载力计算依据和预应力锚杆锚固结构锚固失效判据，为动压锚杆支护巷道支护设计和支护效果评价奠定理论基础。基于应力波原理研究预应力锚杆锚固结构在一定损伤条件下的动态响应规律，阐明预应力锚杆锚固结构健康诊断原理，提出一种基于动力检测的预应力锚杆锚固结构健康诊断方法，为锚杆支护巷道围岩稳定性评价提供实测依据。

随着煤炭开采向深部发展，开采引起的采动压力呈现出强动载特性，动压锚杆支护巷道常因锚固结构锚固失效而出现巷道整体失稳现象。但目前对预应力锚杆锚固结构的损伤机理认识不够，且没有有效的损伤诊断方法，非常有必要在锚固结构锚固失效前掌握其损伤情况并评价其健康状态。本项目采用理论分析、实验室试验、物理模拟、数值模拟和现场测试相结合的综合研究方法，从分析关键层变形破断的准动态力学特征和采动压力分布特点入手，对预应力锚固结构准静态、动态力学行为与损伤机理进行了系统研究。揭示了关键层断裂与岩层移动是引起开采动载的主要因素。关键层断裂时的能量释放与关键层的力学性能及其下方的软弱岩层结构有关，关键层断裂后的煤岩层应力、位移和动力扰动存在分区性和距离效应。.揭示了开采动载作用下的锚固结构损伤与失效机理。采动应力使锚固围岩位移并分层离层，并在锚固界面叠加负指数分布的剪应力，锚固起始端的剪应力增大到一定程度后首先剪切破坏并剪应力降低。随着锚固结构继续承载，锚固体或锚固界面损伤向锚固终止端渐近发展，无围压时峰值剪应力迅速向较深部锚固界面移动并锚固失效；有围压时锚固界面在锚固起始端剪切破坏后仍有较大的锚杆拉应力发展范围。揭示了预应力锚固结构动态损伤机理。树脂锚固体具有明显的粘滞效应和应力增强现象,预应力锚杆的树脂体因长径比效应易在动应力波作用下拉剪破坏，影响锚固极限承载力的发挥。.揭示了预应力锚固结构损伤无损检测原理。随着损伤的发展，树脂锚固层粘接强度较低，锚固段开始位置的反相波峰值与入射波峰值的比值逐渐减小，锚固段结束位置的同相反波峰值与入射波峰值的比值却逐渐增大，这是判断树脂锚固层锚固性能优劣的主要依据。得到了预应力锚杆锚固结构锚固状态健康与否的标志性参数。锚固体或锚固界面损伤、轴向载荷和锚固极限承载力是评价预应力锚杆锚固结构健康状态和预应力锚杆锚固系统是否失稳的标志性参数，同时，研究了标志性参数对预应力锚杆锚固系统动力学特征及其失稳的影响机制。在综合前述研究成果的基础上提出了预应力锚杆锚固结构锚固状态健康诊断的弹性波无损检测原理，开展了系统的无损检测方法和检测有效性研究，研究结果表明：通过检测预应力锚杆锚固结构的有效锚固长度、轴向载荷和锚固极限承载力这三个参数是能够有效地对其锚固状态做出评价的，对提高深部动压巷道围岩稳定性和支护安全可靠性具有重要的现实实践意义。