Study on failure mechanism and acoustic emission characteristics of outburst proneness coal rock under dynamic and static loading

The damage caused by rock burst in coal mine roadways is serious,and the coal rock with burst tendency has the potential to generate failure.Under high stress,it is prone to damage after being disturbed by dynamic load,and its damage and deformation laws are different from conventional staticload.Taking the coal rock with burst tendency under high stress in deep coal seam roadway as the research object to explore the failure and deformation law of coal rock with burst tendency under dynamic and static loads.The dynamic triaxial test and acoustic emission test equipment are used to simulate the high stress environment and dynamic load conditions of coal rock.By comparing the static load failure test under different confining pressures,the dynamic load induced test under a certain stress level,the dynamic loading test atdifferent stress stages to analyze the deformation and failure mechanism and the evolution law of acoustic emission energy.The results show that the dynamic load causes the coal rock to enter the yield deformation in advance and the strength deteriorates obviously.Compared with the static load,the damage degree becomes more serious,and the shear failure transforms into the transverse tensile failure; the acoustic emission point can effectively locate the coal rock fissure development area and the main direction of destruction.There is the critical static load when the coal rock reaches the dynamic load failure condition; the fracture and strain growth of the coal rock will be gradually stabilized under the dynamic load disturbance if the critical static load is not reached,and the rapid destruction will occur after the critical static load.the storage elastic energy of coal rock increases after the dynamic load,which releases more energy than the static load at failure.The energy events of coal rock mainly occur in the initial stage of dynamic loading and the stage of peak failure under confining pressure.There is obvious kaiser effect after dynamic loading.The research conclusion is that the evolution law of acoustic emission energy has reference value for identifying the stress state of coal rock and the initial dynamic load stress level.