| Linhuan coal mine belongs to Huaibei mining co.,LTD.,is located in the southwest of Huaibei Sui Xi County,mine about 13km long,4～5km wide,north and south,the area of about 50km~2,well field structure complexity for class,hydro-geological type is medium,for the thickness of the whole hidden coal field,occurrence,middle and lower three seam groups,which 10 group coal seam mining is threatened by a variety of water damage,especially the coal seam bottom plate karst ash water disaster risk is the biggest.The 1067 working face studied in the paper is located in the six mining area,the elevation of the working face roadway is-413.9～-618.6m,the water pressure of the limestone aquifer in the bottom plate is up to 4.5～6.5MPa,which has the characteristics of high pressure,large water system,large inclination and complex fault structure,can achieve safe and efficient mining?What kind of water damage engineering measures for prevention and control should be adopted has become one of the technical problems to be solved urgently.Therefore,it is very necessary to carry out the safety evaluation of premining water prevention and control on the 1067 working face of confined water.On the basis of consulting the relevant theory and frontier technology of the water penetration mechanism and water damage control technology at home and abroad;Combined with the characteristics of the hydro geological conditions of the 1067working face,Analyzed the water penetration source that may occur during the mining process,Designed and constructed down hole transient Em and Audio electric perspective,The 1067 hydro logical and geophysical abnormality area of working face top and bottom plate are obtained;According to the Detailed Rules for Water Prevention and Control in Coal mine,Calculate the number of 10 coal bottom limestone;Using the"large well method"and the hydro-geological"co MParison method",Estimate the water inflow;Using the dense short drilling hole,the limestone water is discharged quickly;According to the drilling column around the working face,Construct the analysis model of mining floor failure,It reveals the dynamic change characteristics of stress and displacement of floor limestone water and surrounding rock during mining,The possibility of water burress was evaluated.The research contents and the main results obtained are shown as follows:(1)1067 The working face is located in the sixth mining area,Towards the long1176.6～1245.5m,T-tilt length 230.0m,Elevation-413.9～-618.6m,main mining of 10coal seam,Thick 0.40～8.79m,On an average of 3.13m,Tilting angle of 3～32,On average,the average 11,Using comprehensive mechanized mining,The lower distance from the too-grey aquifer is 53.12m,With a bearing limestone water pressure of up to4.3～6.3MPa(the initial water level of the excessive ash aquifer is about+15m),The calculated number of primary burst water systems was 0.08 to 0.118,According to the surrounding 2017-View 1-hole drilling pumping test,Its unit water inflow is q=0.01824L/s m,Weak water-rich nature,It has the characteristics of high water pressure,rich water,uneven and large water system.(2)Hydro-geology and high-density 3 D seismic refinement data of 1067working face are analyzed,Designed and constructed down hole transient Em and Audio electric perspective,To detect the water richness of the rock layer within 100m at the bottom depth of the coal seam,Obtain 2 geophysical hydro-logical anomalareas,For the abnormal area,Arrange 6 down hole verification boreholes,Total borehole length of 940 m,The water output of drilling holes 1#,2#and 3#and 4##is 0,The water output of drilling hole 5#is 5 m3/h,Initial water pressure is 0.2MPa;The initial water quantity of the 6#validation hole is 5 m3/h,Initial water pressure:0.3MPa,Overall,the water output of each borehole is small or has no water,The results indicate a water water city.(3)According to the working face surrounding drilling,combined with the detection results of geophysical exploration technology and top bottom rock measured physical and mechanical parameters,constructed the mining bottom plate destruction evolution analysis model,using the FLAC3D numerical simulation method simulation on the confined water mining bottom rock mass destruction distribution characteristics,rock stress distribution,confined water distribution and seepage law,to simulate the working face mining process,study the bottom plate deformation damage characteristics under mining conditions.(4)According to 1067 working face water source,rich and high water pressure,the original water system,draw lessons from adjacent working face limestone water treatment experience,design and construction of 76 limestone drilling and 6geophysical exploration anomaly verification drilling,drilling total 17344m,construction to four ash,31 hole water,the maximum water is 79.1m3/h,the maximum outlet pressure of 1.0MPa,after discharge limestone water level is-452.4m,indicating that the bottom ash water level has been from the original+15m rapid drop to-452.4m.(5)The"big well method"and the hydro-geological"co MParison method"are estimated,and the"big well method"is 28.0m3/h to estimate the normal water inflow of the working face is 5.5 m~3/h.Co MPare the two methods to estimate the actual water inflow of the working face,and then make the drainage system design of the working face.(6)Through layer dense short drilling drain,bear the water pressure is greatly reduced,using the method of"penetration water number"and the calculation formula of coal seam floor water penetration water system and floor damage depth calculation,it is concluded that the hydrophobic pressure down coal seam floor penetration water system is 0.048MPa/m,bottom plate water damage maximum depth of 30.896m,meet the requirements of the coal mine water control rules,mining is safe and feasible.In conclusion,from the perspective of water damage prevention and safe mining in the working face,the conditions of under-pressure mining are available under the premise of monitoring,monitoring,drainage and emergency measures in the process of working face mining.As of March 2023,the working face has been 826m,goaf water output is less than15.0m~3/h,the paper using geophysical prediction and drilling validation,numerical simulation analysis results and wear dense short drilling advance of hydrophobic water prevention and control technology is safe and reliable,for similar to limestone water threat coal mining has wide application value.Figure[38]table[11]reference[66]... |
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