Study On Development Characteristics Of Fault Structure And Water Control In Mining Area Of Northern Anhui Province

The geological and hydrogeological conditions of the northern Anhui mining area are complex,and the fault structures are developed.Many collapse columns are explored or exposed,and magmatic rock intrusion exists in some areas.In the process of mining,there are many water disasters such as loose layer water inrush,fault water inrush,collapse column water inrush and separated layer water inrush,which seriously threaten the safety of mine production and bring great hidden dangers to the development of deep coal resources and the recovery of shallow coal resources.Based on the geological and hydrogeological data of northern Anhui mining area,this paper analyzes the development characteristics of fault structures in northern Anhui mining area by using the theory of structural gradual control.According to the drilling data and pumping water test data in the area,the contour maps of the main aquifer water level and unit water inflow are plotted,and the hydrochemical characteristics of groundwater are analyzed.The groundwater in the mining area is controlled by the fault structure,and the following conclusions are drawn:1.According to the development characteristics,scale and sedimentary differences of the faults,the fault system in Northern Anhui mining area is divided into three levels,including two first-order structural units,five second-order structural units and 16 third-order structural units.The first grade fault is a regional large fault,which controls the basic hydrogeological conditions of coal field and is the basis of coal field division;The secondary faults control the boundary of the mining area and the division of the mine boundary.Some faults with large plane extension length in the mining area are also classified as secondary faults;There are a large number of third-order faults,mainly the faults with small plane extension length inside the mine.2.There are four types of structural styles in the northern Anhui mining area:normal fault and its extensional structural style,thrust fault and thrust nappe structural style,translation fault and strike slip structure and inversion structure.The typical structural styles of normal faults are graben,Horst and domino;The structural styles of thrust faults are thrust,compression and thrust nappe.Generally,the northern Anhui mining area is an extensional structure.The coal controlling structural styles in the study area are mainly regional fault basin and small-scale Horst of each mine field.The coal controlling faults are mainly high angle straight faults.The eastern nappe structure area and local complex structure area are mainly rotary plane or shovel faults;The compressional faults are represented by the Xu Su arc nappe structure,in which the imbricate thrust structure is the most prominent.3.The controlling effect of fault structure on groundwater is reflected in the hydrodynamic conditions and hydrochemical characteristics of groundwater.The main features are as follows:in the areas with high development degree of fault structures or dense faults,the water abundance of aquifer is enhanced,and the water level is obviously increased;The salinity of the aquifer on both sides of the water blocking fault increases,and there is a certain correlation between the changes of ion content in the aquifer on both sides of the water conducting fault;Moreover,the ion content in groundwater is obviously different with different fault layers.4.There are three water control modes of fault structure in Northern Anhui mining area,which are water blocking mode,water conducting mode and water storage mode.Figure[51]table[10]reference[62]...