Study On Pressure Mining On Confined Water In 9102 Fully Mechanized Caving Face In Lanxian,Shanxi Province

The mining of coal seams in our country often occurs disaster accidents caused by water-rock coupling water inrush,large in quantity,wide in area,threatened by water damage,that resulting in a great loss of economy,but also the destruction of the original environment of groundwater.At the same time,it has caused serious influence and harm to the society.This paper is based on the engineering background of Changheng 9102 fully mechanized top coal caving face in Lv Liang mining area of Lanxian County,Shanxi Province.There are Ordovician ash aquifer on the face,water in the goaf of 4 coal mines,F1 fault near the cut hole,and the hydrogeological conditions are complicated.Therefore,it is very necessary to carry out the feasibility study of 9102 fully mechanized top-coal caving working face with pressure mining.Therefore,basis on the consulting the technology of water damage prevention and control in the domestic and international papers of pressure mining,combined with the data of borehole exposed around the mining area,using the means of surface detection,underground transient electromagnetic detection,audio frequency electrical perspective detection and radio wave detection,etc.To analyzed the hydrologic and geological conditions of the mining area,the characteristics of strata structure and the structural characteristics of geological strata with systematically and concretely.The trial studied the physical and mechanical properties,micro-composition and water barrier properties of geological rocks in this paper,analyse the working face flood factors.The main conclusions are as follows:?1?The overburden rock of No.9 coal roof and floor in 9102 face is soft-medium hard stratum,which has better separation and water-blocking ability.?2?Water accumulation?4 coal?,fault water,9 coal roof,bottom sandstone fissure aquifer and 9 coal floor O ash aquifer in goaf are the main water hazard factors in 9102working face.?3?Bored grouting reinforcement in the geological anomaly to prevent water gushing and water inrush.There are 12 drilling holes in geophysical anomaly area,the engineering quantity is 1109.2 m,and the cement is injected into 38.45 tons.The rock stress changes and displacement changes by the FLAC3D simulation software.The conclusions are as follows:the surrounding rock's mining pressure diversification and displacement diversification will increase when the goaf range,mining surface widththe width and the advancement speed increase.These parameters in the middle of working area is larger than its in the top,it means setting water barrier should on the basis of the damage range of the middle of working area.Predicted the water inrush of 9102 working area respectively,and the water inrush amount of the working area during mining by the"big well"method and the hydro-geological condition comparison method.The results show that the normal water discharge is 50m3/h and the maximum inrush is 120.0m3/in9102 working area.Design the drainage scheme,according to the water consumption and drainage capacity of the working area.The height prediction of the two zones and the height of the safe coal pillar for sand control are calculated.The calculated height of the maximum water diversion fracture zone is 81.43 m,which is more than 61.45⁷6.77 m between 4 coal and 9 coal.The safe mining can be realized.The maximum water inrush coefficient is calculated by the method of water inrush coefficient.The water inrush coefficient ranges from 0.030⁰.045MPA·m^-1,which is smaller than the critical water burst value of 0.06 MPA·m^-11 in the block damaged by the structure.The Tas range of the maximum thickness ratio of safe aquifer is 0.4538⁰.5768,which is less than that of safety system.According to the number of 1,it is concluded that the possibility of water inrush in working face is less.Therefore,on the basis of prevention and control of water damage,combined with the successful experience of other similar working faces,the conclusion of safe mining in 9102 face has been drawn.