Fractal characteristics and its application in electromagnetic radiation signals during fracturing of coal or rock

The present study analyzed the electromagnetic radiation （EMR） time series of the destruction process of coal or rock sample under uniaxial loading and the monitoring process in working face by means of frac- tal geometry, and results of the correlation dimension change curve of EMR time series were obtained. In the meantime, the current study also sought the fractal characteristic to the EMR signals by contrast to the change curve of EMR signals and explored the precursory phenomenon of rock burst. This paper con- cluded the main findings as followed： the EMR time series of the destruction process of coal or rock sam- ple under uniaxial loading and the monitoring process in working face corresponded to fractal： the correlation dimension of EMR time series reflected the process of coal or rock damage deformation, that is, the inner damage of coal or rock made a change from random to order. In the field application, the correlation dimension served as a new index of forecasting the coal or rock dynamic disaster.