频繁强振和高应力环境下深部节理化岩巷变形累积转化特征及其失稳机理

IIn the face of the increasing of mining depth and intensity in metal mine, the coupling influence of frequent blasting vibration and high geostress to rock mass stability is more and more broad. However, the cognitions about several questions for this kind of situation, such as the macro and micro mechanical response of deep fussured rock, the deformation evolution process of this surrounding rock, and the explaination for failure mechanism of this rock laneway, are also inadequate. Aiming at above scientific issues, taking the typital underground metal mines of Yuntong group and Yunxi group in Yunnan as an example, through the the combining methods of macro tests and micro tests, experimental study and numerical simulation, theoretical analysis and field monitoring, the forming, developing and evolution laws of microstructure and the response characteristic of macro mechanical behavior for deep highly-stressed fussured rock under frequent strong viberation are researched, and the cumulative effect and transform characteristic of deformation and failure for fussured rock mass from rock failure to local distortion of rock mass to big deformation of rock laneway is discussed. On the basis of comprehensive analysis the test results, real deformation conditions and field monitoring data, the triggering condition to fussured rock laneway from small deformation to big failure under dynamic-static coupling loading is described, at last, the failure mechanism of deep high geostress fussured rock laneway induced by frequent strong vibration is introduced. The research results will provide a theoretical foundation for the safety production and disaster prevention of underground metal mine, meanwhile, which are also a furthur improvement and supplement to the discipline theory systems of rock mechanics and mining engineering.

面对金属矿山开采深度和强度的越来越大，由其所引起的高地应力和频繁高强爆破振动耦合作用影响日益广泛，对该种条件下深部节理化岩石在宏微观特性上会产生何种响应，该类围岩的变形破坏会如何演变，由其组成的岩巷失稳机理又该如何解释等问题的认识仍然不足。本项目针对上述科学问题，以云南云铜集团、云锡集团等比较有代表性地下金属矿山为研究对象，采用宏观试验和微观测试、试验研究和数值模拟、理论分析和现场监测相结合的方法，研究频繁强振下深部高应力节理化岩石的细微观结构发展演化规律和宏观力学行为响应特征，探讨从岩石破裂到岩体局部变形再到岩巷大变形破坏形式演变的累积效应与转化特征，阐述动静组合条件下节理化岩巷由小变形发展至大破坏的触发条件，揭示频繁强振诱使深部高应力节理化岩巷失稳的作用机理。研究成果将为地下金属矿山灾害的防控和安全生产提供理论依据，同时也是对岩石力学和采矿工程学科理论体系的进一步完善和补充。

随着金属矿山开采深度的不断加大，深部岩石将处在高地应力的环境之中，同时会受到反复的爆破振动作用，其耦合影响对岩巷稳定性及其安全运行具有重要意义。然而，针对深部含原生裂隙岩石的力学特性响应规律、爆破振动对岩石（巷）损伤累积效应及其稳定性影响等问题的研究仍然较为缺乏，对岩石在不同冲击振动条件下力学特性的系统性研究仍显不够。针对上述科学问题，本项目重点开展了含原生裂隙岩石的力学特性试验，单纯冲击、一维动静、三维动静等条件下的力学试验，实施了爆破振动的现场测试，研究了岩石破裂演化过程及裂隙对岩石宏观力学特性的影响规律，探讨了动静组合条件下岩石的变形、强度、能量耗散及破坏规律，分析了岩巷在静应力与振动荷载下的稳定情况，研究成果可为深部岩石复杂条件下力学特性的掌握以及金属矿山深部开采时的安全设计提供理论支持。主要成果如下：1、原生裂隙对岩石的强度和变形特性影响显著，单轴抗压强度、弹性模量均表现出随着大开孔隙率的增大而减小，且降低幅度先大后小的特点；另外，原生裂隙的分布会对岩石破坏模式产生影响，在单轴压缩作用下存在张拉破坏、拉剪复合破坏和沿裂隙面剪切破坏三种类型。2、岩石的动态抗压强度表现出明显的应变率效应。而且冲击方式不同，岩石的破坏模式亦不一样，纯冲击表现为拉伸破坏，一维动静时为剪切破坏，三维动静组合下则呈现出圆锥体或圆锥台型的压剪破坏模式。3、反复爆破振动会对围岩损伤产生累积效应，但影响范围有限，当爆破振动区域距离岩巷越来越远，累积损伤作用便不再显著。4、爆破地震波有着往低频带发展的趋势，若爆破药量适当，则爆破振动对岩巷稳定性的影响不大，但在爆破药量过大时，爆破振动的影响不容忽视。从应力与位移监测结果上看，同样说明爆破震动会对岩层移动产生较为明显的影响。