Feasibility Study On Drainage Of Limestone Aquifer Of Taiyuan Formation In 87 Panel Of Zouzhuang Coal Mine

The 87 panel is located on the western side of Zouzhuang Coal Mine.It is in the narrow and long block between Nanping fault and F25 fault.Nanping fault is a impervious boundary.F25 fault pushes the limestone aquifer of Taiyuan formation to the coal-bearing strata of Permian,and the water pressure reaches 8MPa above 72 and82 of the main mining coal seam.The distribution of the two faults in space is"eight-shaped"or"herringbone",which makes 87 panel form a unique hydrogeological unit.This paper studies the feasibility of drainage and the suggestion of drainage through long-term observation,formula calculation,numerical simulation,identification of hydrogeological parameters,verification of hydrogeological conditions,acquisition of groundwater seepage law,and study on the feasibility of drainage and suggestions for drainage.The main results are as follows:?1?The influence radius and permeability coefficient of 1-4 limestone aquifer in Taiyuan formation are 5200m and 0.074m/d respectively according to the preliminary observation data of water exploration and discharge.?2?According to the special water releasing test,the permeability coefficient is0.16m/d and the average conductivity coefficient is 8.2m²/d by using the Dupuit formula of steady flow;The average water conductivity and release coefficient are33.51m²/d and 6.51×10^-5,respectively by using the Theis distribution method of unsteady flow.?3?The aquifer of Taiyuan formation limestone is generalized to three-dimensional heterogeneous,isotropic and unsteady flow groundwater system.On the basis of parameter identification and structural fractal dimension optimization,the numerical software is used to identify the parameters.The hydrogeological model of limestone aquifer of Taiyuan formation in 87 panel is established.The model proves that the relative error of water level is between 3%and 18%,and the correlation coefficient is above 0.9.?4?On the basis of the model,according to the distance of 40 m,three discharge points are set up in the drain roadway,and the average discharge capacity is 30m³/h.The water level of the limestone aquifer of Taiyuan formation can be drainaged to the level of 72 coal seam floor.The water level of limestone aquifer of Taiyuan formation generally lower than 60 m of 72 coal seam can be obtained by setting up 6 discharge points according to the distance of 40 m and the average discharge amount of 20m³/h.At present,the discharge of 87 panel is 94m³/h,and it is expected that the total discharge of the south wing of 87 panel will be further increased 90-120m³/h to reduce the water head to below 72 coal seam floor.?5?From the aspects of hydrochemical characteristics,structure and boundary conditions,water releasing test and numerical simulation results,it is shown that the limestone aquifer of Taiyuan formation is relatively independent from Quaternary aquifer,Ordovician aquifer and sandstone fissure aquifer on top and floor of coal seam.The direct recharge is limited to the deep limestone aquifer of Taiyuan formation.The coal seam floor in the 87 panel is high in the south and low in the north,and the difference in the floor of the coal seam from south to north in the face is more than 300m.It is feasible to reduce the water level of limestone aquifer of Taiyuan formation to the bottom of coal seam.