Study On Mechanism And Control Technology Of Rock Burst Induced By Hard Coal In Steeply Inclined Thick Coal Seam

The rock burst induced by unstable failure of hard coal rock mass in steeply inclined extra-thick coal seam under the influence of mining is one of the main problems faced by steeply inclined coal seam in Urumqi mining area after entering deep mining.The geological structure and coal seam occurrence conditions in the northern mining area of Wudong Coal Mine are complex.Under the influence of tectonic stress,a large amount of elastic energy is accumulated in hard coal and rock mass.In the process of mining,fractures gradually develop and eventually lose stability and damage,thus releasing a large amount of energy,resulting in frequent rockburst accidents.In this paper,through the field geological conditions investigation,laboratory rock mechanics and physical simulation experiment,theoretical analysis,numerical calculation and field engineering practice of combining research methods,the steeply inclined thick coal seam hard coal rock induced impact mechanism and control technology were studied.Taking the north mining area of Wudong Coal Mine as the research background,through field geological survey,it is found that the horizontal tectonic stress field is the main stress field in the north mining area of Wudong Coal Mine.The elastic energy of coal and rock accumulation increases with the increase of mining depth,which is easy to induce rock burst accidents.Through rock mechanics experiments,it is concluded that the relevant physical and mechanical parameters and 43#、45#coal seams and their roof and floor have weak impact tendency.The physical similarity simulation experiment based on real-time monitoring of microseismic equipment reveals the energy evolution and distribution law of steeply inclined hard coal and rock mass during mining,determines the core area of energy release,and divides the critical depth of northern mining area according to the field investigation results.The impact risk of unmining level was predicted by b-value characteristic curve.The research results effectively alleviate the problem of rock burst in the northern mining area of Wudong Coal Mine,and provide a scientific basis for ensuring the green,safe and efficient mining of steeply inclined thick coal seam.Through three-dimensional numerical calculation software,the influence law of mining technical parameters(section height,mining sequence and advancing speed)on rock burst induced by hard coal and rock mass in steeply inclined working face is mastered,and the difference analysis is carried out respectively.Combined with physical similarity simulation experiment,the mechanism of rock burst induced by steeply inclined hard coal and rock mass under deep mining conditions in northern mining area is revealed,and the mining parameters with good effect of elastic energy accumulation and conduction are determined,so as to prevent and control rock burst from the source of disaster.On the basis of selecting suitable mining parameters to control rock burst from the source,combined with the measures of roof shallow hole water injection and deep hole blasting technology,the rock burst is comprehensively controlled,and the control effect is tested by borehole TV and transient electromagnetic.The research results effectively alleviate the problem of rock burst in the northern mining area of Wudong Coal Mine,and have important reference significance for the safe and efficient mining of steeply inclined thick coal seams under similar conditions.