Fracture Evolution Regularity of Surrounding Rock Under Different Interlaminar Strata Structure in Short-Distance Coal Seams Group: A Case Study in China

In order to study the fracture evolution regularity of surrounding rock under different interlaminar strata structure in short-distance coal seams group, based on the background of the coal seam group in a Shendong Coal Mine, the interlayer structure was classified using key strata theory. Four UDEC numerical models were established according to the distance between two coal seams and the number of inferior key strata, the main conclusions were drawn as follows: when there was only one inferior key stratum between the two coal seams, the increase of the distance between these two coal seams has little effect on the fracture evolution of the overburden rock mass; the location and number of inferior key strata affect the dynamic development and distribution of overburden fractures, while it would not affect the height of fracture distribution; the two inferior key strata with same properties and thickness would decrease the range of fracture distribution. The conclusion of this study is of great theoretical significance for coal mine gas drainage and water hazard control.