Study on the characteristics of micropore size structure of stratified coal samples after dynamic loading

In order to study the influence of the microstructure change law of coal sample and the structural anisotropy of coal mass on the microstructural change law after dynamic loading(impact loading),the Hopkinson experimental system(SHPB)was used to impact the coal samples in different directions to different degrees.The low-temperature liquid nitrogen adsorption test of coal samples before and after impact loading,the micro-aperture structure characteristics of coal samples under different impact loads were compared and analyzed.The results showed that the micropore content of the impacted coal sample was significantly lower than that of the original coal sample,and the micropore content gradually decreased with the increase of the impact load.Under the impact loading,the microstructure of the coal sample had a tendency to transform from micropores to small pores and small pores to medium and large pores.With the increase of impact loading,the total pore volume,specific surface area and adsorption amount had a t