【摘要】 层理对煤岩体宏、细观力学性质都有重要影响。为探究不同层理方向煤岩体的损伤演化规律及变形破坏中的声发射特征,分轴向平行层理和轴向垂直层理2种情况进行煤岩制样,采用MTS815岩石力学试验系统和PAC声发射仪,开展单轴加载条件下破坏全过程的声发射(AE)试验研究,揭示煤岩AE时序参数、能量释放规律、空间演化特征和AE振幅分布的层理效应。研究表明:相对于轴向垂直层理煤岩,轴向平行层理煤岩在整个受力过程中AE振铃计数和能量释放更强,但单位时间的AE振铃数和能量释放更平缓,轴向垂直层理煤岩呈现急剧猛烈的能量释放特征;轴向平行层理煤岩中,一定规模的AE事件在更低应力水平就会产生,其AE空间分布更加均匀,无轴向垂直层理煤岩的成核现象;在变形破坏全过程中,轴向平行层理煤岩AE振幅分布变化幅度较小,其b值更大,大尺度AE事件比例更低。研究成果在一定程度上反映了煤矿开采过程中工作面和上覆煤岩的层理方向对其声发射特征的影响,可对现场声发射监测围岩破坏情况提供借鉴和参考。更多还原

【Abstract】 Bedding planes have a great influence on the macroscopic and microscopic mechanical properties of coal. In order to explore the damage and AE characteristics of coal with different directions of bedding plane during the deformation and failure,the coal samples were prepared in two types,i.e. the axis of the samples parallel to and perpendicular to the direction of bedding plane. Experiments on acoustic emission characteristics during full-regime failure of samples under uniaxial compression were carried out with the rock testing system MTS815 and PAC AE. The AE ring-down count and energy release of the samples with the axis parallel to bedding plane are stronger during the whole loading process,while the AE ring-down count and energy release in unit time interval are smoother compared to the samples with axis perpendicular to the bedding plane. The coal samples with the axis perpendicular to the bedding plane display the drastic energy release characteristics. Certain amount of AE events occur at the lower stress level in the samples with axis parallel to bedding plane and the AE distribution spatially are more homogenous,and there were no nuclear phenomena. For the samples with the axis parallel to the bedding plane during the deformation and failure,the variation of AE amplitude distribution is smaller,b value is greater and the proportion of big AE events is smaller.更多还原