Study On The Association Response Mechanism And Characteristics Of Electromagnetic And Microseismic Signals During The Deformation And Fracture Of Coal Or Rock

The association response mechanisms and change characteristics of electromagnetic andmicroseismic signals in the process of deformation and fracture of coal or rock are studied byadopting the method of a combination of theoretical analysis, experimental research and field testin the dissertation. According to electromagnetic field theory, fracture mechanics and damagetheory, the mechanical characteristics of coal and rock crack propagation are analyzed.Meanwhile, the generation mechanism and influence factors of low frequency electromagneticsignals and microseismic signals are studied. Afterwards, the electromagnetic and microseismicsignals during the deformation and fracture of coal and rock under different loading (constantvelocity loading, variable velocity loading, multi-stage loading, impact loading) are tested byusing ZDKT-1coal and rock dynamic disasters experimental simulation system. Through theEnsemble Empirical Mode Decomposition (EEMD) and wavelet threshold denoising method, thehigh and low frequency mode of electromagnetic and microseismic signals are determined. Andthe effect of loading conditions and the composition and structure of specimens onelectromagnetic and microseismic signals is analyzed. Then, the correlation of electromagneticsignals, microseismic signals and stress is studied by means of the correlation analysis. Theassociation response characteristics of electromagnetic and microseismic signals in the aspect offrequency and energy are analyzed based on the energy accelerated release and critical pointtheory, and the prediction method of instability and failure of coal and rock on the basis ofassociation response of electromagnetic and microseismic signals is proposed. Finally, the electromagnetic and microseismic signals of coal fracture induced by blasting excavation inheading face are investigated, and the joint prediction of the source location by usingelectromagnetic and microseismic signals is preliminarily attempted.