Numerical Simulation Of A Mine In Ordos And Prediction Research Of 18 Coal Seam Floor Water Inflow

Mine water has an important impact on coal mining,not only affects the cost of mining,but also poses a threat to the safety of coal mining.Water inrush accidents occurred in the mining process of the coal seam in the study area,which caused the coal mine to stop production.The water inrush source came from the sandstone aquifer in Baotashan.In order to ensure the mining safety,this paper takes Baotashan sandstone aquifer as the research object,simulates and calculates the water inflow of a working face of 18 coal seams to be mined in this mine,and predicts the floor water inflow of the working face.According to the characteristics of groundwater flow in the target aquifer,a three-dimensional unstable seepage model of confined,heterogeneous and anisotropic aquifer is generalized,and the corresponding mathematical model is established through the seepage model.The conceptual model of hydrogeology is established by generalizing the conditions of aquifer boundary,hydraulic connection and recharge and drainage.The numerical model of the study area is established by regional discretization,permeability coefficient partition and input of initial hydrogeological parameters.And a numerical model which conforms to the actual hydrogeological conditions is established by adjusting the parameters of the study area and fitting of observation holes data.According to the calculation of floor water head pressure value and water inrush coefficient formula of 18 coal,the critical water level of normal block is+916.481 m,and that of structural damaged block is+816.491 m.The simulation software Visual Modflow is used to simulate the floor water inflow of a working face in the study area.And the simulation results are 573.49 m~3/h and 742.003 m~3/h.The prediction of normal water inflow by big well method is 542.73 m~3/h and 669.710 m~3/h.The water inflow calculated by the numerical simulation method is larger than the normal water inflow by the large well method,and the water inflow calculated by the numerical method is closer to the reality,so the numerical method is selected as the basis for the safe mining of the mining area.