Study On The Effect Of Outburst-proneness Of Coal By Gas Pressure

With the arrival of the deep mining era,the dynamic disasters appeared in more and more mining,especially the dynamic disaster occurred in gassy coal often shows the characteristic of coupling dynamic disaster both with coal outburst and rock burst.In the past,the research about rock burst mostly still stays on the basis of the theory of the rock burst is the outburst ignored or without the gas effect,and the coal outburst-proneness indexes in our country industry regulation are obtained through uniaxial compression experiment under the condition of the coal samples without gas.Hence,the research analyzed the influence rule of coal and rock mechanical behavior by gas pressure for the purposes that the influence of outburst-proneness indexes by gas pressure.A set of experimental equipment that the coal samples deformation and failure under uniaxial compression condition of coal and rock containing gas was researched and developed with RMT-150 C rock mechanics test system as the carrier,and then,constituted a gassy coal uniaxial compression experiment system with DS5 AE monitoring and signal analysis system and XL2101 C SPC static resistance strain gauge.The study measured and analyzed the mechanical parameter,outburst-proneness index and AE signal in the process of uniaxial compression under different gas pressure.Then,the study simulated the destruction process of the coal sample,the mechanical parameter and the characteristic of AE signal spatial distribution under different gas pressure.Last,the study established coal sample damage equation by using the theory of dissipative structure.The mainly conclusions:(1)The experimental results: As the internal gas pressure of coal sample increased from 0 MPa to 2 MPa,The compressive strength and elastic modulus of coal samples respectively decreased by 58.78% and 49.03%,and its Poisson's ratio increased by 27.43%.The outburst-proneness indexes of coal samples,namely dynamic failure time,elastic energy index,impact energy index and uniaxial compressive strength,showed a trend of lower,and the outburst-proneness of coal samples changed from strong to weak.The AE peak counting,AE peak energy,AE accumulative counts and AE accumulative energy also showed a trend of decrease.(2)The simulation results: The study found that the development of fracture and the distribution of AE signal in the coal sample failure process developed from disorderly to orderly.With the increase of gas pressure,the simulated specimens' loading force(compressive strength)and elastic modulus showed a trend of decrease.The AE peak counting,AE peak energy,AE accumulative counts and AE accumulative energy of samples showed a trend of decrease.Simulation results were consistent with the experimental results.(3)The theoretical results: Based on the dynamic equation of the theory of dissipative structure,the study derived the equation of fractal dimension in the progress of uniaxial failure changed over time.The results showed the greater the gas pressure,the more discrete the deformation and the bigger the fractal dimension.The calculation results is consistent with the test and the simulation results.