Study On Prediction Of Rock Burst By Surface Subsidence In Coal Mine

Surface subsidence and rock burst are two kinds of environmental geological disasters with strong destructiveness.The occurrence of surface subsidence is due to the movement of coal seam roof and overlying strata to the surface,which will lead to the damage of buildings,farmland,roads and other facilities on the ground;The occurrence of rock burst is due to the movement and stress redistribution of coal roof and overlying strata caused by mining disturbance,which eventually leads to the tensile instability of surrounding rock,and the coal and rock mass are quickly thrown out in a very short time,resulting in damage.It can be seen that both surface subsidence and rock burst are affected by the movement of coal seam roof and overlying rock,so monitoring surface subsidence can be used to predict rock burst.In order to get the connection between the two,taking West No.3 mining area of Hongyang No.3 coal mine as the object,the linkage mechanism between surface subsidence and rock burst is studied by using the methods of theoretical analysis,ABAQUS numerical simulation and similar material simulation.Combined with the actual monitoring data,the method of applying surface subsidence to evaluate the risk of rock burst is proposed.Taking the gob roof and overburden movement as the common factors,the occurrence mechanism of surface subsidence and rock burst as well as their respective characteristics are studied respectively.Through comparative analysis of the similarities between the two,it is pointed out that there is correlation between surface subsidence and rock burst.The numerical model of finite element analysis is established to study the strata movement and stress distribution during mining.The relationship between surface deformation and internal overburden stress is obtained,that is,when the surface subsidence rate begins to accelerate,the strata near the goaf may reach the state of high accumulation stress,and it is very likely that the strata near the goaf will continue to be strongly disturbed Rock burst occurred.The similar material simulation experiment was used to study the surface subsidence and stress change law under different roof thickness conditions.The stress change law,overburden movement law and coal pillar displacement law after mining were analyzed.It was concluded that when the surface subsidence rate suddenly decreased,it may be that the roof above the goaf becomes thicker and energy accumulation has occurred in the rock stratum,it is likely that there will be impact ground pressure.According to the actual geological conditions of the mining area,the surface subsidence monitoring system is optimized for the target working face.Combined with the results of simulation experiment,the method of applying surface subsidence to predict rock burst and risk assessment is proposed.The study summarizes some laws of overburden movement and stress change under different conditions,obtains the relationship between surface subsidence and rock burst,and finally applies the research results to rock burst prediction and risk assessment in mining area,so as to provide basis for coal mine safety production.