Experimental study on acoustic emission characteristics of impact tendency coal under combined dynamic and static loading

Using DTAW-8000 rock high-pressure dynamic test system and acoustic emission technology, through uniaxial compression tests with different dynamic load disturbance frequencies, the relationship between fracture characteristics and acoustic emission characteristic parameters of impact tendency coal under dynamic and static combined loading is studied, the whole process of impact tendency coal compression damage is analyzed, and the damage evolution model is established. The results show that with the increase of dynamic load disturbance frequency, the main fracture angle of coal rock with impact tendency decreases first and then increases, and the stress and strain both decrease; the development and expansion process of internal fractures in coal rock with impact tendency are closely related to acoustic emission signal, the cumulative number of acoustic emission ringing changes in the whole process of coal rock compression can be roughly divided into stable stage, sudden increase stage and slow increase until failure stage; the trend of coal and rock damage evolution model is consistent with the test data; the frequency of dynamic load disturbance is the main factor that affects the time history of coal rock fracture in the stage of slow-rapid growth of coal rock damage.