Research on evaluation indices for impact tendency and danger of coal seam

Aiming at the rockburst tendency indices could't completely impact dangerous degree of coal seam,the new impact energy speed indicator considering the time effect,the critical soften areas coefficient and the critical stress coefficient were put forward.Four traditional indices such as dynamic damage time,elastic energy index,impact energy index and uniaxial compressive strength in combined with the proposed three new indices were used to estimate the impact tendency risk of the coal seam.The test results of the coal samples show that the three new evaluation indices and the traditional indices,to a certain extent,are able to accurately assess the impact tendency and hazard from rock burst of the coal seam.