Reliability analysis of coal crushing failure probability and its classification application

Abstract：The coal crushing phenomenon can be considered as a problem of failure probability. On the basis of coal crushing prediction model established by using Hock-Brown criterion, the coal complete reliability was defined based on reliability method, and the calculation method of coal crushing failure probability was proposed. According to the magnitude of coal crushing failure probability, four grades of A, B, C, D were divided for coal crushing degree, and the coal crushing classification standard was determined. Using the classification method, the coal crushing degree was an- alyzed for Well ZS-P4 in Qinshui Basin,and the relation between coal crushing failure probability and the influence factors was discussed. The results show that the coal crushing failure probability of Well ZS-P4 is among 0.6-1.0 ; the corresponding distribution pattern is high for roof and floor coal formation and is low for central coal formation;the coal crushing failure probability for coal formation section at depth 811.4-812.0 m is 1 ,which can be defined as grade A; the prediction results of coal crushing degree agrees well with experimental results observed by electron microscope; the coal crushing failure probability presents nonlinear growth relationship with horizontal principal stress difference in- creasing and uniaxial compressive strength reducing.