Research On Roadway Rockburst Induced By Mine Earthquake

In mining engineering,the dynamic load caused by mine earthquake is an important factor to induce roadway rockburst,and the damage degree of roadway is often more serious than that of rockburst with static load instability.In order to solve the problem issued above,the mechanism of roadway rockburst induced by mine earthquake is studied through methods combined with field investigation,statistical analysis,theoretical research,similar simulation test,numerical simulation and field test.A softening zone energy extremum criterion for roadway rockbursts is proposed,and the critical softening zone energy and other indexes of roadway rockburst are given.The influence of roadway surrounding rock properties on rockburst critical indexes is studied systematically.And the influence of mine earthquake waves energy at softening zone outer boundary and critical softening zone energy on roadway rapid shrinkage displacement is studied.Finally,based on theoretical study of roadway rockburst induced by mine earthquake,An anti-seismic and rockburst prevetion design method of rodway is put forward and applied in coal mines.The main contents of this paper are as follows:(1)The mechanism and characteristics of mine earthquake are analyzed.The surface shallow buried WiFi microseismic real-time monitoring and positioning system is developed independently.Based on the statistics and analysis of microseismic data of typical rockburst mines,the distribution rules of source energy,source spacing and original time interval of mine earthquakes are obtained.The attenuation law of mine earthquake energy with propagation distance is studied,and relation formula of mine earthquake energy with propagation distance is obtained.The mine earthquake-rockburst roadway instability system is established,and the effect of mine earthquake energy on inducing rockburst is revealed.(2)The elastic-plastic softening model of circular roadway is established,and the analytical solution of surrounding rock softening zone energy of roadway rockburst is obtained.The softening zone energy extremum criterion of roadway rockburst is put forward,the critical softening zone energy,the critical roadway shrinkage displacement,the critical roadway shrinkage rate and the critical softening zone radius are given.The ratio of mine earthquake waves energy at softening zone outer boundary to critical softening zone energy is defined as the uniform energy index.The softening zone energy extremum criterion of roadway rockburst induced by mine earthquake is put forward.When the uniform energy index is less than or equal to 1,there is no excess energy released into the roadway,and the roadway rockburst will not be induced.When the uniform energy index is greater than 1,the roadway rockburst will be induced.Then,the similar simulation test is carried out by using the self-developed static and dynamic combination two-directional loading two-dimensional simulation test system,and combined with the numerical simulation method,the correctness and rationality of the theoretical study of roadway rockburst induced by mine earthquake are verified.(3)The methods of surrounding rock bursting liability classification and roadway bursting hazard evaluation are studied,through methods combined with theoretical analysis and tests.The critical softening zone energy and the uniform energy index are used as the bursting liability and bursting hazard indexes respectively.And the analysis shows that,the smaller the critical softening zone energy,the stronger is the bursting liability.The greater the uniform energy index,the stronger is the bursting hazard.Subsequently,based on the critical softening zone energy and the uniform energy index,the bursting liability classification and bursting hazard classification are carried out.(4)The influence of mechanical properties and structural parameters of surrounding rock on rockburst critical indexes are analyzed,through methods combined with theoretical analysis and numerical simulation.The results show that,the critical softening zone energy increases exponentially with the increase of uniaxial compressive strength and roadway radius,but decreases exponentially with the increase of deformation modulus index and elasticity modulus.The critical roadway shrinkage rate decreases exponentially with the increase of deformation modulus index and elasticity modulus,and increases linearly with the increase of uniaxial compressive strength,but does not change with the change of roadway radius.The ratio of critical softening zone radius to roadway radius decreases exponentially with the increase of deformation modulus index,but does not change with the change of uniaxial compressive strength,elasticity modulus and roadway radius.(5)The influence of critical softening zone energy and mine earthquake waves energy at softening zone outer boundary on roadway rapid shrinkage displacement are analyzed,through methods combined with theoretical analysis and numerical simulation.The results show that,When roadway rockburst is induced by mine earthquake,the larger the critical softening zone energy,the smaller is the roadway rapid shrinkage displacement,which presents an exponential downward trend with the increase of critical softening zone energy.The larger the mine earthquake waves energy at softening zone outer boundary,the larger is the roadway rapid shrinkage displacement,which presents a linear upward trend with the increase of the mine earthquake waves energy at softening zone outer boundary.(6)The anti-seismic and rockburst prevetion design method of rodway is proposed to resist roadway rockburst induced by mine earthquake through energy absorption of surrounding rock and support system.The method is applied in Gengcun coal mine and Hongyang No.3 coal mine.And through the analysis of application effect,it is proved that the anti-seismic and rockburst prevetion design method of roadway is reasonable and reliable,which is of great significance to ensure the safe and efficient mining of coal mine.