Abstract: In order to research the risk of water inrush from coal floor of Shanxi formation No.3 coal seam in No.5 and 7 mining areas in,according to the data of geology,hydrogeology,fault and borehole of the research area,the fault distribution characteristics of the research area are systematically analyzed.On this basis,fractal method and water inrush coefficient method are used to study the fault structure complexity and water inrush risk in No.5 and 7 mining areas.The results show that the evaluation results have a good match between the fractal method and water inrush coefficient method although the calculation principle and quantization parameters of the two methods are different.It is concluded that the coal seam floor in the No.5 and 7 mining area has a high fractal dimension in the northeast,complicated geological structure,and large water inrush coefficient,which should belong to the danger zone of water inrush,the southeast area belongs to the relative danger zone of water inrush,and the west area belongs to the safety zone.The results of this study have important reference value for the safety belt pressure excavation and water hazard prevention and control in No.5 and 7 mining areas.

Key words: fault structure,fractal dimension value,water inrush coefficient method,quantization division,mining area