Research On Rock Mass Structure Characteristics And Water Inrush Risk Of The No.10Coal Seam Floor At Qingdong Mine

The safety exploition of No.10coal mining in Qingdong coal mine is threatened by the water from Taiyuan formation and Ordovician. Geological stress affects the area in history. There are many faultage and fold. The floor of coal seam is broken. It is easy to happen the water inrush accident Analyzing the hydrogeological features of the aquifer of limestone of Taiyuan formation and the character of the structure of rock mass. Researching on the possibility of water inrush in the study area.Analyzing the hydrogeological features of the aquifer of No.1-4limestone of Taiyuan formation.The result show the water permeability and watery of No.1-4limestone of Taiyuan formation are weak to moderate. Degree of development of karst is low. Content of TDS is high. Type of water quality is SO4～Ca·Mg. Using method of "large diameter well" and analogy to predict water yield,the normal water inflow is380m3/h, the maximum water inflow is550m3/hSecondly,counted and analysed rock mass structure characteristics of the No.10coal seam floor in research area,studied the basic elements of coal seam floor thickness,rock properties,sandstone percent based on borehole data.The results show that the No.10coal seam floor has a comparatively integrated rock mass structure,the water-resisting and compressive property are good as a whole,it also has the risk of water inrush in local structures develop zone.Think about the damage of coal seam floor by exploiting. Using FLAC3D to establish the fem-numerical model, simulate the damage condition of exploit in floor.The result show that the number of the maximum depth of damage is15m.Select five factors to see as the evaluation index,such as fractal dimension value, thick of No.1-2limestone of Taiyuan formation, sand factor, core recovery of limestone of Taiyuan formation, effective thickness of coal seam floor. Based on grey theory and fuzzy mathematics, establish the mathematics model to evaluate the dangerousness of water inrush in study area.By the result, partition the study area by the dangerousness of water inrush. The results show that most of the study area is relatively safe,safe region is comparatively small,the total of two area occupies70%of the study area,the rest threatened area and danger area have the poor location in study area.To check the balance of model,analysis the parameter sensitivity between the parameter and model, level of sensitivity between model and parameter conform to the reality.The model is reasonable.Provide the data support for mastering the condition of limestone water and the geological basis for the safety exploition of No.10coal mining.