Analysis of the evolution characteristics of infrared energy of coal samples under composite disturbance of dynamic and static loads

Coal deformation and damage are the fundamental causes of mining disasters. This paper proposes an intelligent sensing method of infrared thermal imaging applied to the characterization analysis of deformation and damage of coal mass during loading. The thermal infrared imager and crack monitoring equipment were used to jointly monitor the average infrared radiation temperature (AIRT) and damage pattern of coal samples under the combined disturbance of dynamic and static loads during uniaxial loading. The time–frequency characteristics of infrared radiation during the destruction of coal samples were analyzed; a crack recognition model based on Mask R-CNN was constructed to identify and detect different crack shapes after the destruction of coal samples. The results show that the uniaxial compressive strength of the coal sample under static load is greater than the combined disturbance of dynamic and static loads, the degree of deformation and damage of the coal sample is more severe, and the cracks are more obvious; the uniaxial compressive strength of the coal sample under the combined disturbance of low-frequency dynamic and static loads is higher than that of the high-frequency composite disturbance of dynamic and static loads. Composite disturbance of frequency, dynamic and static loads; a DST analysis method for coal sample fracture and a new index of coal sample damage degree are proposed. The research results can provide reference for early warning of coal and rock deformation and damage.