Risk analysis of water inrush from coal seam floor: a case study of No.12 coal seam floor in Qianjiaying coal mine, Tangshan city

Qianjiaying coal mine of Tangshan is located in the south-east wing of Kaiping syncline with complex geological conditions.In order to explore the risk of water inrush from the floor of No.12 coal seam in Qianjiaying coal mine, based on boreholes and hydrogeological data of the mine, the main geological factors affecting water inrush from the floor of No.12 coal seam in the Qianjiaying coal mine are selected as the water pressure of Ordovician limestone, the thickness of aquifer, the thickness of effective brittle strata and the distribution of faults and folds.The analytic hierarchy process is used to evaluate the main controlling factors and to determine the structure matrix.By calculating the weights of the main control factors, introducing the risk assessment model and choosing the reasonable limit value for the data, the zoning map of water inrush risk assessment of No.12 coal seams in Qianjiaying coal mine is finally obtained.The study shows that the possibility of water inrush from the floor of No.12 coal seam in Qianjiaying coal mine is relatively high, especially in the northeast area where the structure is relatively developed.By comparing the hydrogeological data of the mine, the evaluation results are in good agreement with the actual situation.This study provides theoretical and technical supports for effective prevention and control of water hazards in coal seam floor.