Experimental Study on Mechanics Properties of Coal Impact Damage

In order to research mechanical characteristics in the process of coal impact failure, SHPB (Split Hopkinson Pressure Bar) device is used to conduct impact damage compression test with different impact speed for 1/3 coking coal samples from Pingmei No.10 Coal Mine. The results show that the range of maximum strain rate of the coal samples is from 85.25 to 168 s^-1 with the impact velocity speed from 3.287 to 12.399 m/s, and the range of limit stress is from 15.84 to 47.33 MPa; with the increase of impact velocity, coal specimen material appears the strain hardening and strain softening phenomenon; with the increase of impact velocity, the average strain rates rapidly increase, then add slowly, and the quadratic polynomial fitting correlation is better, the maximum strain rates also rapidly increase, then increase slowly while reaches a certain value, and present the trend of decreasing slightly, and the cubic polynomial fitting correlation is better.