Experimental study on dependence of infrared radiation on stress for coal fracturing process

Coal rock fracture is the major factor of disasters which occurred because of mine water bursting and the un- stability of coal pillar. Effectively supervising the process of it is extremely important to the water conservation and stra- ta control in mine. It is known that infrared radiation changes with the stress when coal rock is loading. The sudden change index of the variance of infrared radiation temperature of coal under uniaxial compressive loading was proposed to study the quantitative relationship between stress and infrared radiation. The result of this study shows the ratios of IR controlled by stress in cubic coal specimens (50 mm×50 mm×50 mm) and rectangular coal specimens were 93%and 85% . Sudden change coefficient of the variance of infrared radiation temperature which occurs after stress adjust- ment is two orders of magnitude than the coefficient of stress adjustment. Also this control effect has a characteristic of hysteretic,the average hysteretic time of infrared radiation of cubic coal specimens and rectangular coal specimens were about 2. 7 s and 2. 9 s.