Risk Evaluation And Preventing Countermeasures Of Water Inrush From 15~# Coal Seam Floor In Dongshan Coal Mine Of Taiyuan

Coal plays an important role in the national economy of our country,with the increase of the scale and depth of coal mining,the lower coal seam is threatened by the water inrush from the bottom limestone. Long term mining practice shows,for the coal seam with pressure,the risk of water inrush from floor is based on the characteristics of the aquifer, the water resistance performance of the bottom plate,the geological structure,mining activities and other factors. Dongshan coal mine geological structures are well developed,the coal seam floor has been destroyed,and the Ordovician limestone aquifer is rich in water,and the traditional water inrush coefficient method is used to evaluate the water inrush risk of coal seam floor,which can not be used as the basis for safe production.According to the water flood problems of Dongshan coal mine 15~# coal seam floor Ordovician limestone karst,this paper analyzed 15~# coal seam floor of Ordovician limestone water pressure to determine the pressure and non pressure zone based on the identification of the geological environment background in the area,hydrogeological conditions and past water inrush data. It used the vulnerable index method to zone and evaluate 15~# coal seam floor water inrush risk and took the eight main controlling factors of coal seam floor water inrush of Ordovician limestone as vulnerability evaluation index of the influence through the study on the mechanism of water inrush from coal floor and forecast method. The main control factors of the original data were quantified and interpolated and the main control factors attribute database was established and thematic maps were generated by using the attribute assignment function and spatial interpolation function of ArcGIS. It analyzed the main control factors and calculated the weight of the main control factors on the total target by using the AHP analytic hierarchy process,the main control factor normalization thematic map was weighted superposited according to the weight value to generate a topological relationship of composite layer by using the AHP weight calculation method and GIS powerful spatial analysis ability combination,so as to establish 15~# coal limestone floor water inrush prediction and evaluation model. It concluded the Dongshan coal mine 15~# of coal seam floor water inrush vulnerability zoning map by determining the partition threshold of floor water inrush risk of comprehensive zoning evaluation,and divided the risk of water inrush from 15~# coal seam floor into five zones,which were the vulnerable zone,the more vulnerable zone,the transition zone,more safe zone and relatively safe zone. Evaluation results show that the risk of water inrush from the Ordovician limestone aquifer in the 15~# coal seam floor of Dongshan coal mine shows a tendency from west to East,the water inrush danger zone is mainly concentrated in the west of mine and the fracture zone and the intersection point of the fault,more than half of the area is a transition zone,the more vulnerable zone and vulnerable zone in the study zone and the transition zone and more vulnerable zone,even in vulnerable zone are in the developed structure zone,such as fault and subsided column.The vulnerability index method and the traditional water inrush coefficient method were compared and analyzed,results show,the vulnerability index method comprehensively considers the influence of the main control factors on the water inrush from coal seam floor,and reflects the relative vulnerability of different regions,the evaluation results are more scientific and reasonable,and the real and reliable.In this paper,based on the evaluation of vulnerability zoning,referring to the experience of the prevention and control measures of karst water in the north of china,based on the geological,hydrogeological features and production practice in the study area,the prevention measures and suggestions for the coal seam floor Ordovician limestone water inrush are proposed for the different vulnerability zones,Dongshan Coal Mine 15~#,the safe mining and the karst water environment protection provide the technical support and the scientific basis,has the reality and the theory significance.