Resarch On Geodynamic Conditions And Dynamic System Of Coal And Rock In Wudong Coal Mine

Surface elevation of Wudong coal mine is+800 m.B3+6 and B1+2 are the two suberect and extremely thick coal seams in Wudong coal mine,which thickness are 40 m and 30 m respectively,and dip angle of them are 87° on average.Rockburst accident has appeared for 5 times in Wudong coal mine since 2011,which providing serious threat to the safety of production.Rockburst risk of Wudong coal mine will further enhance with the depth of mining and tunneling extend to the deep gradually,thus providing serious problems of being solved urgently to Wudong coal mine.Based on the theory of plate tectonics in this paper,theoretical analysis method,numerical calculation method,similar material simulation method,geo-dynamic method and rock mass analysis method are used to research the rockburst accidents happened in extremely thick coal seams of Wudong coal mine.Physical mechanical parameter characters and rockburst proneness of coal and rock are tested in laboratory,and feasibility experiment of water injection is completed.Stability of rock pillar is respectively analysed before and after coal mining at each mining level by similar material simulation method.The influlence of mining on displacement and stress of the rock pillar is revealed,and the effect of the hard rock pillar on rockburst is also ensured.Geo-dynamic condition evaluation method and corresponding index system are built in this paper,geo-dynamic conditions of rockburst in suberect and extremely thick coal seam of Wudong coal mine are evaluated by this method.Geo-dynamic condition evaluation results show that the geo-dynamic conditions of rockburst exist in Wudong mine field,and the geo-dynamic conditions are getting more and more active.Concept of dynamic system of coal and rock is put forward in this paper,model of the relationship between occurrence of rockburst and dynamic system is built at the same time.Calculation method of dynamic system scale and its evaluation system and quantitative indicators are put forward.Dynamic system scale of dynamic nuclear area zone,damage zone,injury zone and influence zone in Wudong coal mine is calculated.On this basis,dynamic system of coal and rock analyse software in Wudong coal mine is developed.which could forecast the risk of rockburst in Wudong coal mine.Rock mass stress state at+500 m mining level in Wudong coal mine is calculated by rock mass analysis system,which is developed by Liaoning Technical University independently.High stress region,stress gradient region,normal stress region and stress reduction region in mining area are divided by the system.Rockburst critical energy density and rational mining strength of Wudong coal mine are ensured combined with FLAC3D numerical calculation method and theoretical calculation method.The coupling effect combined geo-dynamic conditions with mining effect constitute the occurrence mechanism of rockburst in Wudong coal mine.Geo-dynamic conditions and dynamic system of coal and rock are researched in this paper,rockburst risk regions of Wudong coal mine are divided,and different risk degrees in different regions are certained.On this basis,rational mining strength of Wudong coal mine is ensured.The research will improve the technical level of rockburst prevention and control,which could provide a theoretical guidance to rockburst prevention and treatment of Wudong coal mine and other coal mines with similar conditions.