Zhangjiamao Coal Mine Coal Mining Of Phreatic Water Field Of Perturbation Law Research

Jurassic coal field in Northern Shaanxi province is located at the junction of shaanxi andlnner Mongolia of the wind beach area, the surface is Mu Us Sandy Land with fragileecological environment, the Salawusu phreatic water aquifer and Jurassic coal resources arewidely distributed below it. All of them constitute the organic connection system of ecologicalenviroment, water resources and coal resources in the vertical space. When coal mining formwater-flowing fractured zone can conduction Salawusu aquifer, will make a valuableecological phreatic water aquifer collapse into the underground, on the one hand, a seriousthreat to the safety of mine production, on the other hand, the production and living waterdepletion caused by local residents, serious impact on the local ecological environment.Therefore, the analysis of the impact of coal mining on the hydrogeological conditions, tostudy the flow field characteristics of coal resources exploitation before and after theecological phreatic water and coal mines to prevent mine water damage and protect the mineecological phreatic water significance.In this paper, taking ZhangJiamao coal mine in Shenfu mining area as the research object,identified coal mine ecological phreatic water and key impermeable layer in the depthdirection and lateral distribution characteristics and variation, study the seam-groundwatercombination of space relationship and hydrogeological engineering geological characteristicsof component units, divided coal seam-water space combination of relationship type, builddifferent combinations of coal seam-water space relationship of rock-hydraulic structureconceptual model, analysis of the basic features of the ecological phreatic water flow fieldbefore mining. By compared empirical formula, FLAC3Dnumerical simulation and measuredvalues obtained ZhangJiamao coal mine2-2seam mining the ratio of the height of the cavingzone to the mining height than7, the ratio of the height of the water-flowing fractured zone to the mining height than16. Basis impermeable layer of impermeable stability criterion,summed up the influence of mining disturbance under water-flowing fractured zone of criticalimpermeable layer impermeable stability, draw the phreatic water field corresponding to themain coal seam in mining affect dropout degree of partition, application of empirical formulacalculated the coal mine specific coalface water-flowing fractured zone radius of influence for1046m. With the flow field simulation software based on finite difference Modflowgroundwater, the radius of influence of the water-flowing fractured zone formed by theanalysis of nearly horizontal seam mining for1655m. Obtain result before ChangJiagoureservoir surrounding coal seam mining ecological phreatic water water level up to1260m, aminimum of1180m, the phreatic water field flow northwest to southeast, after the seammining ecological phreatic water the water level up to1260m, a minimum of1120m, the flowof water flow field around for coal mine to bring together the goaf. ChangJiagou reservoirsurrounding coalface safe distance of about1655m.For other mining areas as the same geological conditions as ZhangJiamao coal miningarea, the research results had certain guiding significance, which also provided theory andtechnological basis for water resources, ecological environment protection and coal mining inecological fragile mining area in Northern Shaanxi.