Prediction And Formation Mechanism Of Water In Bed Separation Of Coal Seam Roof In Yonglong-binchang Mining Area

Coal plays an important role in the development of our national economy. But with development of the coal mining, it generates the mine water disaster issues has been caused a serious threat to the safety of the mine’s production. Recently, the Yonglong-Binchang mining area is a newly-develpoment mine in Shaanxi province, its coal seam thickness is large and quality is good, but the water disaster in bed separation in coal seam roof is serious in mining. Therefore, carried out the mechannism and its predicting methods research of water disaster in bed separation has important and practical value for preventing water disaster of coal seam proof and ensuring the safety of the mine’s production.Based on analyzing the mine geology, hydrogeology and water gushing data of working face of Dofosi and Guojiahe mine in Yonglong-Binchang mining area, it can be realized that its water gushing of workingface has the characteristics of the water in bed separation in recent years. By using the method of theoretical analysis and numerical simulation to analyze and calculate the overlying strata characteristics and its combination relationship, mechanical parameters and the formation conditions of water in bed separation of working face, it can be obtained the following conclusions. The space of bed separation formed between the hard and soft rock, the combination of overlying hard rock(sandstone) and underlying soft rock(mudstone) is the basic condition for its forming, the uncoordinated deformation of the hard and soft rock is its primary cause; The water in bed separation which can lead to water disaster is generally developed on the top of fractured zone, its source is the water in sandstone aquifer of the overlying strata above the bed separation, it can be formed the water inrushing when fractures spread it; the formation and inrush of the water in bed separation has the characteristic of periodicity; due to the differences of overlying rock of Dafosi and Guojiahe mine, the location of water in bed separation which can formed the water disaster is different and periodic distance of water inrush is varying, but are all located between the bard and soft rock; the space of bed separation which can lead to water disaster is located between the sandstone in the middle of anding formation and sandy mudstone in the top of anding formation and conglomerate in yijun formation and sandy mudstone in anding formation in Guojiahe coal mine; the location of space of bed separation which lead to water disaster is between the conglomerate in yijun formation and mudstone in anding formation.On the basis of the combination relationship of overlying strata and analyzing of water supply to predict developing position of bed separation which can store water of 41105 working face in Dafosi coal mine. By using the numerical simulation method to predict the position of bed separation which can be stored water with the change of the mining. The volume of water in bed separation of working face has been calculated based on the empirical and equivalent fracture methods. Combination the conclusion of the theoretical analysis and numerical simulation, it can be analyzed that the devlopment law of the water in bed separation and water volume. By comparison with the actual situation of gushing, it can be proved that predicting of the position and volume of the water in bed separation by the above method is reasonable. Researching results has important guiding significance for predicting and preventing water disaster in bed separation of working face in Yonglong-Binchang mining area and other similar mining area.