Liu Jiajia, Yang Di, Hu Jianmin, Yu Baozhong, Nie Zishuo
School of Safety Science and Engineering, Henan Polytechnic University, Jiaozuo, Henan 454003, China.
State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines, Anhui University of Science and Technology, Huainan, Anhui 232001, China.
ACS Omega. 2023 Jun 5;8(24):22168-22177. doi: 10.1021/acsomega.3c02470. eCollection 2023 Jun 20.
Bedding has an important influence on the macroscopic and microscopic mechanical properties of coal, and the mechanical properties of coal and rock mass and acoustic emission characteristics are very important for rock burst monitoring and warning. In order to explore the influence of different beddings on the mechanical properties and acoustic emission characteristics of high-rank coal, using the RMT-150B electrohydraulic servo rock mechanics test system and the DS5 acoustic emission analyzer, the uniaxial compression and acoustic emission characteristics of high-rank coals with different beddings (parallel bedding 0°, oblique bedding 30, 45, 60°, and vertical bedding 90°) were investigated. The results show that the uniaxial compressive strength and deformation modulus of vertical stratified coal samples are the largest, which are 28.924 MPa and 2.95 GPa, while the average values of uniaxial compressive strength and deformation modulus of oblique stratified coal samples are the smallest, which are 10.91 MPa and 1.776 GPa, respectively. With the increase of the bedding angle, the uniaxial compressive strength of high-rank coal decreases first and then increases. The stress-strain process of coal varies greatly with different high stratification grades (parallel bedding 0°, oblique bedding 30°, 45°, 60° and vertical bedding 90°). The loading times of parallel, oblique, and vertical beddings are 700, 450, 370, 550, and 600 s, and the acoustic emission mutation point values are 495, 449, 350, 300, and 410 s. The mutation point value can be used as precursor information to judge the failure of high-rank coal in different beddings. Research results to find the high-rank coal destruction instability prediction method and the index provide a basis; further damage to the acoustic emission testing high order coal provides reference significance; and the use of acoustic emission in the monitoring and early warning of percussive ground pressure, the bedding surface of coal, and the actual stress on site should be considered.
层理对煤的宏观和微观力学性质有重要影响，煤岩体的力学性质及声发射特性对冲击地压监测预警至关重要。为探究不同层理对高阶煤力学性质和声发射特性的影响，利用RMT - 150B型电液伺服岩石力学试验系统和DS5声发射分析仪，研究了不同层理（平行层理0°、斜层理30°、45°、60°和垂直层理90°）高阶煤的单轴压缩及声发射特性。结果表明，垂直分层煤样的单轴抗压强度和变形模量最大，分别为28.924MPa和2.95GPa，而斜分层煤样单轴抗压强度和变形模量的平均值最小，分别为10.91MPa和1.776GPa。随着层理角度的增大，高阶煤的单轴抗压强度先减小后增大。不同高分层等级（平行层理0°、斜层理30°、45°、60°和垂直层理90°）煤的应力 - 应变过程差异较大。平行、斜向和垂直层理的加载时间分别为700、450、370、550和600s，声发射突变点值分别为495、449、350、300和410s。突变点值可作为判断不同层理高阶煤破坏的前兆信息。研究成果为寻找高阶煤破坏失稳预测方法及指标提供了依据；对进一步开展高阶煤声发射试验研究具有参考意义；且在冲击地压监测预警中利用声发射时，应考虑煤层理面及现场实际应力情况。
