1School of Safety Engineering, China University of Mining & Technology, Xuzhou, China
2Key Laboratory of Gas and Fire Control for Coal Mines, Xuzhou, China
Received: 03 Jan 2014 – Discussion started: 04 Apr 2014
Abstract. Dynamic collapses of deeply mined coal rocks are severe threats to miners; in order to predict collapses more accurately using electromagnetic radiation (EMR), we investigate the spatiotemporal multifractal characteristics and formation mechanism of EMR induced by underground coal mining. Coal rock in the burst-prone zone often exchanges materials (gas, water and coal) and energy with its environment and gradually transitions from its original stable equilibrium structure to a nonequilibrium dissipative structure with implicit spatiotemporal complexity or multifractal structures, resulting in temporal variation in multifractal EMR. The inherent law of EMR time series during damage evolution was analyzed by using time-varying multifractal theory. Results show that the time-varying multifractal characteristics of EMR are determined by damage evolution processes. Moreover, the dissipated energy caused by the damage evolutions, such as crack propagation, fractal sliding and shearing, can be regarded as the fingerprint of various EMR micro-mechanics. The dynamic spatiotemporal multifractal spectrum of EMR considers both spatial (multiple fractures) and temporal (dynamic evolution) characteristics of coal rocks and records the dynamic evolution processes of rock bursts. Thus, it can be used to evaluate the coal deformation and fracture process. The study is of significance for us to understand the EMR mechanism in detail and to increase the accuracy of the EMR method in forecasting dynamic disasters.
Revised: 26 Jun 2014 – Accepted: 08 Jul 2014 – Published: 15 Aug 2014
Hu, S., Wang, E., and Liu, X.: Spatiotemporal multifractal characteristics of electromagnetic radiation in response to deep coal rock bursts, Nat. Hazards Earth Syst. Sci., 14, 2089-2103, doi:10.5194/nhess-14-2089-2014, 2014.