Experimental investigation of acoustic emission and infrared radiation thermography of dynamic fracturing process of hard-rock pillar in extremely steep and thick coal seams

摘要

This paper aims to analyze the stability of a hard-rock pillar (HRP) sandwiched between extremely steep and thick coal seams (ESTCSs). Acoustic emission (AE) testing and thermal effect of infrared radiation thermography (IRT) results are indicators of the physical characteristics of rock mass fracture under high stress. This paper provides the method connecting AE testing and IRT characteristics to predict dynamic and gas hazards by physical experimental model. Relationships between AE testing and IRT are reflected in the conversion of elastic energy to thermal energy (Thermo-elastic Effect) and friction-producing thermal energy (Frictional Thermals Effect) as the HRP failure. In addition, the HRP surface shows that infrared areas clearly migrate during coal seam mining disturbances. This indicates the dynamic fracture development in the HRP. These relationships indicate that dynamic hazards can easily induce gas hazards in ESTCSs. Certain associated indicators provide some guidelines for the prediction and prevention of dynamic and gas hazards in situ.