Study On Variation Of Stress-electricity-thermal Of Composite Coal Rock In Deformation And Fracture Under Load

Coal-rock dynamic disaster is a kind of phenomenon with dynamic effects and disaster consequences that coal-rock happened under the action of external stress in very short time.Electromagnetic emission(EME)in deformation and fracture under load of coal and rock can effectively quickly predict rock bursts,coal and gas outburst and other dynamic disaster.It can realize the non-contact continuous dynamic forecast.Subject adopts interdisciplinary theory.Research effective and reliable coal-rock dynamic disaster prevention technology from the applied basic theory,technology and equipment development.The main research results are as follows:Coal-rock under load electromagnetic radiation frequency band is very wide.The mechanism of different frequency bands have differences.The loaded and rupture of macro,microscopic mechanism is more complicated.Electromagnetic radiation produce by under load composite coal-rock is the result of all sorts of radiation mechanism under the different load level and different condition of load.The project has developed coal-rock EME signal collection and processing system based on DSP+FPGA,and improved antenna structure,and had a test.The solution is perfect.The project presents a EME signals denoising algorithm based on adaptive empirical mode decomposition(AEEMD)and improved wavelet thresholding(IWT),and simulation and experimental results show its superiority.We have studied distribution of electromagnetic radiation intermediate frequency signal in different stages of composite coal-rock under load and fracture.EME signals and internal infrared radiation and temperature of loading composite coal-rock fracture have been studied to obtain their variation and mechanism and the relationship curves among stress,electromagnetic radiation and infrared radiation.The results also show that the interior of the coal,roof and floor sandstone infrared radiation temperature and strain,stress and temperature all have strong linear positive correlation through linear fitting.EME and infrared radiation temperature was triple correlation.By loading experiments of composite rate coal with different rate,electromagnetic radiation,infrared radiation signals signal and charge induction signals are showed increasing trend of premonitory,but the trend is not fully synchronized.By infrared thermal imaging the project has studied infrared radiation of composite coal-rock and mudstone samples unstable fracture in surface and show that precursor emerges certain regularity.Composite coal-rock simulation models have been established considering different combinations,mechanical parameters,confining pressures and inclination by FLAC3D.Strain,elastic modulus,shear modulus and other parameters show a certain regularity.The simulation and experimental result shows that the models are accurate.Stress-electricity-thermal coupled model of loading composite coal-rock deformation and fracture has established considering thermal injury and its accuracy has been improved through experiment.The research results have a very important theoretical significance and practical application value for improving electromagnetic emission basic theoretical system of coal-rock,further reveal evolution mechanism of coal and gas outburst and other disasters,improve the prediction method of coal-rock dynamic disaster such as coal and gas outburst and to ensure the safety of coal mine.