Evaluation Of Water Bursting Risk From The Roof Of 2^-2 Coal Seam In Hong Liulin Coalmine

The coal-bearing strata of Hongliulin coalmine are Middle Jurassic Yan'an Formation.The 2-2 coal seam studied in this paper is located at the top of the fourth section of Yan'an Formation,which is the top coal seam in the field.There are multi-layer aquifers on the coal seam.The exploitation of 2-2 coal seam will mainly be affected by weathered bedrock aquife of Middle Jurassic Yan'an Formation and Zhiluo Formation and Quaternary loose sand aquife in future.In this paper,the FLAC3D numerical simulation software is used to simulate the development of water flowing fractured zone after 2-2 coal mining.Comparing the simulated crack production ratio with the mining of Daliuta coalmine 2-2 coal mining formation water flowing fractured zone,we can use simulated crack production ratio to predict the height of water flowing fractured zone to the coal mine coal mining 2-2 after comprehensive analysis.The 2-2 coal to weathered bedrock aquifer and loose sand aquifer in the distance subtracts the height of water flowing fractured zone minus the predicted,according to whether the result is less than 0,breakthrough range distributio is generated.Coal 2-2 overlying the two layer aquifer is divided into a breakthrough zone and no breakthrough region.Respectively,using different methods of weathered bedrock aquifer and loose sand aquifer evaluates the water enrichment and zoning.Among them,the weathering of bedrock aquifer is 2-2 coal direct water filling aquifer and rich water.In order to maximize the realistic description of the rich water aquifer,this paper chooses 5 main influence factors of weathered bedrock water rich.Generates thematic maps and get the weight by variationG1-Coefficient of Variation method.The 5 main factors of integration construct the comprehensive evaluation index of weathered bedrock water rich water abundance index,and the index of 2-2 coal overlying weathering bedrock aquifer of rich water assessment and zoning.Loose sand aquifer is the indirect water filling aquifer 2-2 coal,and 2-2 coal in most regions due to the distribution of water,the area of spring flow and pumping test data combination has carried on the water enrichment evaluation and zoning.The weathering of bedrock aquifer and loose sand aquifer water partition map correspondto the breakthrough of the stack area distribution,generating surge risk zoning map of water.The results show that the weathered bedrock aquifer,only the West an area near the border of west region is relatively safe area,and the eastern boundary line vitalisk areas and erosion along the border is a dangerous area,and the small area in the danger zone,a wide range of central region is the transition zone;for loose sand aquifer,the water water in the scope of most areas without water had little effect on 2-2 coal mining.