Research On Influences Of The Primary Key Stratum On Evolution Of Water Flowing Fractured Zone

Mining-induced fracture of rock strata is the primary influence factor to form the passage of water bursting, and the evolution rule of fracture in rock mass by mining can provide important theoretical basis for the judgment of the mine water bursting occurrence conditions, forecasting water bursting and formulating the countermeasures to prevent the mine water disaster. Therefore, further research on the height of water flowing fractured zone and the influencing factors of water flowing fractured zone is of great importance of theory value and engineering meaning.Based on summarize and analyze previous research results, this paper researches on the influences of the location of the primary key stratum on the development of the hight of water flowing fractured zone and the block structure movememt of key strata breakage on the dynamic evolution of water flowing fracture, with the problem of abnormal water bursting from roof in No.4 panel of bulianta mine in Shendong mining area as engineering background, on the basis of the key strata theory in ground control, using theoretical analysis, similar simulation, numerical simulation and field measurements ect research method. The results showed that different positions of the primary key stratum have great influence to the height of water flowing fractured zone. At the same condition, when the primary key stratum on the down position, the height of water flowing fractured zone is higher than the primary key stratum on the up position. When the primary key stratum on the down position, the breakage of the key strata can conduce jumping mutation of the height of water flowing fractured zone.The key strata periodical breakage and the block structure movement make the overlying strata water flowing fracture above the key strata in the cycle process of"produced- development- closure stable- produced". At the same time, this paper proves up the height of water flowing fractured zone at 31401 working face of Bulinta coal mine, expounds the corresponding relationship between the block structure movememt of key strata breakage and the water level change in the hydrological observation hole, reveals the mechanism of the abnormal water bursting from roof in No.4 panel, predicts the dangerouse water bursting zone of 1-2 coal seam in No.4 panel, and puts forward mining scheme that the work face don't have to backout caving in advance and avoid arrangement the waterdrainage drilling.The research results have already been testified in the mining at 31401 working face in No.4 panel of Bulianta Mine, and field application have achieved good economic benefit.