Analysis on overburden strata movement and mine strata pressure behavior of high cutting mining in ultra thick seam

In order to deeply understand the overburden strata movement and mine strata pressure behavior features,the numerical simulation and the site mine str ata pressure monitoring and measuring method were applied to analyze the overburden strata movement,mine strata pressure behavior and the powered support worki ng resistance features of the high cutting coal mining face in Daliuta Mine. The results showed that the canopy stress amplitude of the hydraulic powered support could be applied to judge the pressurized state of the powered support in the coal mining face and the serious degree of the overburden strata breakdown.When the coal mini ng face was pushed forward with 50 m,the main roof above the coal mining face would have a slicing failure in a small scope.The blasting pre-fracturing could make the main roof to be an asymmetry arch structure.The failure of the arch structure would make the horizontal stress reduced within the rock strata of the main roof and the ve rtical stress would be increased.Thus the roof of the coal mining face would be initially pressurized and the roof pressurized step distance would be 88 m.The articulate d structure at the top of the main roof could make the horizontal stress within the rock stratum of the main roof increased and the vertical stress reduced.The breakdow n of the suspended boom structure underneath would cause the secondary roof strata pressurized and the roof pressurized step distance would be 25 m. The articulated structure failure would make the horizontal stress and vertical stress increased within the rock strata of the main roof and would cause the third roof strata pressurized and the roof pressurized step distance would be 20 m.The instability of the arch structure and articulated structure in the main roof would cause the roof strata pressuri zed seriously and the overburden strata breakdown would be expanded to the surface ground.