基于声发射参量的煤样损伤模型研究

Research on Coal Samples Damage Model Based on Acoustic Emission Parameters

在单轴压缩下煤样损伤模型基本原理的基础上,推导出了基于声发射参量的煤样损伤模型。以原煤为研究对象,在单轴压缩下,对煤样进行声发射实验,验证了基于声发射参量的煤样损伤模型在煤样破坏前是可行的;分析了在单轴压缩下的声发射特性,并提出了基于"归一化"声发射累计计数的损伤变量,得到了在单轴压缩下煤样的应变—损伤方程和煤样的一维损伤本构方程。研究结果表明:声发射参量能够反映煤样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;基于声发射参量的煤样损伤模型是合理的,反映了声发射事件数和煤样损伤之间的对应关系;单轴压缩下的煤样损伤演化过程,可分为初始损伤阶段、损伤稳定演化和发展阶段、损伤加速发展阶段和残余损伤阶段4个阶段。

On the basis of the basic principle of uniaxial compression coal sample damage model, the coal sample damage model based on acoustic emission parameters was deduced. The study fo- cused attention on crude coal and conducted acoustic emission experiments on coal sample under uniaxial compression. It has been proved that the coal sample damage model based on acoustic e- mission parameters is feasible before coal sample is damaged. Also, the coal samplers acoustic e- mission characters under uniaxial compression were analyzed. A new damage variable, which is based on normalized accumulative counting of acoustic emission, was proposed. Both the strain- damage equation of coal sample and the one dimensional constitutive equation of coal sample dam- age under uniaxial compression were obtained. The research results show that the acoustic emis- sion parameters can reflect the compaction of internal primary fracture of coal sample and the process of new fracturers generation, propagation, penetration and evolution. The coal sample damage model on the basis of acoustic emission parameters is reasonable and this model reflects the corresponding relation between acoustic emission events and coal sample damage. The evolu- tion process of coal sample damage under uniaxial compression can be divided into four phases, that is, initial damage, stable evolution and development of damage, accelerating development of damage and residual damage.