| China's economic development is inseparable from coal resources,but China's unique geological and hydrogeological conditions have a great impact on the mining of coal resources.In the process of coal mining,a series of water disasters often occur.Mine water disaster has become one of the main disasters affecting coal mining.Especially in North China and East China,many coal seams are covered with Cenozoic loose layer.There is a confined aquifer at the bottom of the Cenozoic loose layer,which is generally called "the bottom aquifer" or "the fourth aquifer".The aquifer is mainly composed of sand and gravel,with good permeability and non cementation.Most of it is directly developed on the top of coal measure strata,which has an extremely adverse impact on the green and efficient production of coal mine.There have been many water inrush accidents in Suxian mine of Huaibei,so it is very necessary to study the water yield of the fourth aquifer.In this paper,the fourth aquifer of Cenozoic loose layer in Xutuan mine(the"fourth aquifer" for short)is the research object,based on the systematic collection and arrangement of mine geology,hydrogeology and exploration borehole data,and with the main research methods of geological statistics,theoretical analysis and mathematical statistics,it analyzed the sedimentary characteristics of the fouth aquifer,considered the water yield and sedimentation of the four aquifer and determined the influencing factors of water yield,The weight of each index was calculated,and the the fouth aquifer water yield of Xutuan mine was evaluated in different zones,which provides the basis for the safe mining of shallow coal seam.The main research results are as follows:(1)Through the statistical analysis of the lithology and thickness of the fourth aquifer in Xutuan mine,the lithology characteristics and thickness distribution characteristics of the fourth aquifer in the mine were obtained.The lithology of the fourth aquifer was divided into three categories,namely gravel type,sand type and clay type.According to the distribution of lithology and lithofacies of the fourth aquifer,the characteristics of sedimentary facies of the fourth aquifer were analyzed,which were divided into fluvial facies,pluvial fan facies and eluvial slope facies,and the sediments of the fourth aquifer were divided into river alluvial proluvial facies,residual sediments and slope sediments.(2)The main factors affecting the water abundance of the fourth aquifer were determined,including the thickness of the fourth aquifer,the thickness of sand gravel layer,the number of sand gravel layers,the ratio of sand gravel,the unit water inflow and the permeability coefficient;the subjective and objective weights of each water abundance evaluation index were determined by AHP and entropy weight method,and the comprehensive weights of each evaluation index were determined by multiplication synthesis normalization method.(3)Through ArcGIS,the evaluation model of four water bearing capacity index method based on AHP and entropy weight method was established,and the fourth aquifer water abundance of mine was divided into the stronger water rich area,the medium rich water area,the weaker rich water area and the weak rich area.The results show that the unit water inflow rating results were in good agreement with the discriminant results of the model,and the established the fourth aquifer water yield evaluation model was reasonable.(4)Based on the study of the hydrogeological characteristics and the evaluation of water abundance of the fouth aquifer,the flow field of the "four aquifer" was simulated and predicted by GMS.Figure[61]Table[19]Reference[114]... |
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