单轴压缩煤岩损伤演化及声发射特性研究

 为建立声发射参数与岩石(煤岩)力学破坏机制的关系，更好地了解受载煤岩体的损伤演化规律，进一步揭示煤岩动力灾害演化过程及灾害时间效应产生机制，利用MTS815岩石力学测试电液伺服试验系统和8CHS PCI–2声发射检测系统，对单轴压缩煤岩的损伤演化及声发射特性进行试验研究，分析单轴压缩煤岩的声发射特性，提出基于“归一化”累积声发射振铃计数的损伤变量，建立基于声发射特性的单轴压缩煤岩损伤模型，得出煤岩的损伤演化曲线和方程。研究表明，声发射信息反映煤岩内部的损伤破坏情况，与其内部原生裂隙的压密及新裂隙的产生、扩展、贯通等演化过程密切相关，煤岩的声发射特征能较好地描述其变形和损伤演化特性。基于声发射特性的单轴压缩煤岩损伤模型是合理的。单轴压缩煤岩损伤演化过程可分为3个阶段：初始损伤阶段、损伤稳定演化和发展阶段、损伤加速发展阶段。煤岩由变形至破坏可视为一逐渐发展过程：由变形、损伤的萌生和演化，直至出现宏观裂纹，再由裂纹扩展到破坏的全过程。

STUDY ON DAMAGE EVOLUTION AND ACOUSTIC EMISSION CHARACTER OF COAL-ROCK UNDER UNIAXIAL COMPRESSION

In order to study the deformation and damage character under load and to further reveal the evolutionary process and the time effect mechanism of coal-rock，damage evolution and acoustic emission(AE) character of coal-rock under uniaxial compression are studied using MTS815 servo-controlled rock mechanical test system and 8CHS PCI–2 AE system. AE character of coal-rock under uniaxial compression is analyzed. A new damage variable，which is defined based on normalized cumulative ring-down count of AE，is proposed；and the damage model of coal-rock under uniaxial compression is established. Damage evolution curve and equation of coal-rock are obtained. The results show that AE information can reflect internal damage of coal-rock and is closely related with primary crack compression and evolutionary course of new crack generation，growth，and connectivity. AE can describe the deformation and damage evolution character of coal-rock. The new damage model of coal-rock under uniaxial compression is reasonable；the deformation and damage evolution process can be divided into three phases including the stage of initial damage，the stage of damage stable evolution and development，and the stage of damage accelerating development. The development of coal-rock deformation and damage can be regarded to be gradual，which is the whole process from deformation and damage initiation and evolution to the appearance of macroscopic cracks，from macroscopic propagation to damage.