Numerical Simulation Of Floor Fracture Thickness In Mining Coal Seam Above Bearing Water

For a long time, the safe mine of our country's coal resources has been seriously affected by a primary factor which is water inrush from coal seam floor.The fracture of the bottom plate is that the most direct reason for the occurrence of water inrush from the floor of the mining face, which provides the guide channel for the rising water inrush of the underground water.The paper gives summing-up to study fruit of water inrush from coal seam floor, then found the problems and insufficient which still existed in them on basis of integrating statistical analysis of coal mining working face. Researching the floor rupture of thickness which was effected by different mining process and during the process,due consideration is given to the influence of confined water in Ordovician limestone water pressure under the floor of working face, because in the actual production, the water inrush from coal seam floor is the ultinately hazard of working face floor burst. According to the occurrence condition and the geological characteristics of the coal seam, which is analyzed through the analysis of the fault and the formation characteristics, regional geological models were established, then analysis of the study area coal seam mining working face floor thickness of rupture, respectively by computer numerical simulation calculation and experience formula calculation method, which is of great significance.Regional geological models were established which are analyzed through the analysis of the fault and the formation characteristics. The parameter of the model combine to actual parameter of colliery.In this paper, the numerical simulation models of the study area are established respectively in the finite element numerical simulation software Phase2 and the finite difference numerical simulation software FLAC3D. Study the influence of the thickness of the working face floor rupture and underlain by confined water in Ordovician limestone in different mining process of working face floor to judge whether water inrush occurs.On the other hand, empirical formula method is used to study the fracture thickness of the coal seam working face. According to the practical application of engineering, study indicating:? The reason of water inrush from floor is various, and the fracture thickness of bottom plate is very important.? By using the method of numerical simulation, when the working face baseboard layer is thin, the results show that the difference of the mining technology has great influence on the rupture thickness of the bottom plate of the coal seam;? Under the condition that the working face baseboard layer is thin, the choice of appropriate mining technology can effectively control the rupture thickness of the floor;? When the depth of the coal seam is larger and the thickness of the bottom layer is thinner, the thickness of the coal seam mining face floor is greatly different when adopting the technology of slicing mining, strip mining and filling mining;? The numerical simulation model is scientific, and it is feasible to calculate the thickness of the bottom slab of coal seam mining with the method of numerical simulation. And combined with engineering example, the formation mechanics model is applied, respectively using finite element numerical simulation software Phase2 and finite difference numerical simulation software FLAC3D, numerical simulation of mechanical models are established. The result of rupture thickness of working face floor is 11.5m, and the values obtained on the basis of the empirical formula calculation is 11.64m, obviously it is consistent with the result of the numerical simulation results.lt provided a scientific basis for the decision of the mining of the coal mining working face.