Study on coal and rock acoustic emission and infrared radiation characteristics under different loading rates
JIANG Yongxin, LI Zhonghui, CAO Kang, TIAN He, HE Shun, WANG Fengzhi
中国矿业大学 安全工程学院中国矿业大学 煤矿瓦斯与火灾防治教育部重点实验室中国矿业大学 煤炭资源与安全开采国家重点实验室
为了研究煤岩受载破坏过程中不同加载速率下的声发射和红外辐射特征以及破坏前兆信息,进行煤岩在不同加载速率下的单轴压缩试验。试验结果表明:在煤岩试样变形破坏的4个典型阶段,每个阶段的煤岩具有不同的声发射和红外辐射特征,不同加载速率下的声发射和红外辐射规律各基本一致。线弹性阶段红外辐射温度的下降趋势较初始压密阶段略有减缓,在塑性阶段煤岩试样持续升温,温度最低点在线弹性阶段。随着加载速率的增加,平均AE计数和平均AE能量均增大,峰值点附近的声发射活动更为剧烈,峰值处释放的能量的最大值呈递增趋势;红外辐射温度呈现典型的降转升型,温度由降转升点提前;煤岩发生破坏时,温度发生突变,最高红外辐射温度的最大值随加载速率的增大而增大。红外辐射温度与声发射计数呈较高的正相关关系,相关系数达0.79~0.99。不同加载速率下声发射测试结果反映出的试样损伤临界前兆点的波动率为71.3%~95.6%,红外临界前兆点的标准差为0.75~0.92。
In order to study the characteristics of acoustic emission and infrared radiation under different loading rates during the failure process of coal and rock as well as failure precursor information, the uniaxial compression experiments of coal rock at different loading rates were carried out.The results showed that in the four typical stages of deformation and failure of coal and rock samples, the coal and rock in each stage have different characteristics of acoustic emission and infrared radiation and the acoustic emission and infrared radiation under different loading rates are basically the same.The downward trend of infrared radiation temperature in the linear elastic stage is slightly slower than that in the initial compaction stage. In the plastic stage, the coal and rock samples continue to heat up, and the lowest temperature is in the linear elastic stage.With the increase of loading rate, the average AE count and average AE energy increase, the acoustic emission activity near the peak point becomes more intense, and the maximum value of energy released at the peak increases. The infrared radiation temperature presents a typical drop-up type, and the temperature will be advanced from the falling point. When coal and rock are destroyed, the temperature changes suddenly, and the maximum value of the highest infrared radiation temperature increases with the increase of loading rate.The infrared radiation temperature has a high positive correlation with the acoustic emission count, and the correlation coefficient is 0.79~0.99. The volatility rate of the critical precursor point of sample damage reflected by the acoustic emission test results under different loading rates is 71.3%~95.6%, and the standard deviation of the infrared critical precursor points is 0.75~0.92.
acoustic emission;infrared radiation; different loading rates; coal and rock
0 引言
1 试验设计及试验方法
1.1 试验系统
1.2 试验样品制备及加载方式
2 试验结果分析
2.1 煤样变形破坏的4个典型阶段分析
2.2 不同加载速率的煤样声发射、红外特征分析
2.3 不同加载速率的煤样声发射、红外相关性分析
3 结果讨论
4 结论
主办单位:煤炭科学研究总院有限公司 中国煤炭学会学术期刊工作委员会