Study on acoustic emission and infrared radiation characteristics of coal combination with different tectonic coal thickness

In order to study the characteristics of acoustic emission and infrared radiation and the information of failure precursors, uniaxial compression tests were carried out on coal combinations with different tectonic coal thickness. The test results show that in 4 typical stages of deformation and failure of composite specimens, the composite specimens in each stage have different characteristics of acoustic emission and infrared radiation, and the laws of acoustic emission and infrared radiation under different tectonic coal thickness are basically the same. The decreasing 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 rise, and the lowest temperature is in the elastic stage. With the increase of tectonic coal thickness, the AE count and AE energy both decrease. The lower the intensity of AE activity near the peak point, the maximum energy released at the peak point shows a decreasing trend. The infrared radiation temperature showed a typical stable upturn pattern. The temperature changes abruptly when the composite fails, and the maximum infrared radiation temperature decreases with the increase of coal thickness. The range of acoustic emission peak count and maximum infrared radiation temperature of tectonic coal assemblages is 3.24×104 ~ 1.99×104, 5.9 ~ 1.1℃, respectively. The acoustic emission test results of coal samples with different tectonic thickness show that the fluctuation of critical precursory point is 77.0% ~ 99.6%, and the standard deviation of infrared critical precursory point is 0.74 ~ 0.92.