Research On Overlying Strata Fracture And Strata-pressure Behavior About Extremely Thick Coal Seam By Fully Mechanized Caving Method In Tongxin Mine

Tongxin coal mine is the second ten million tons coal mine of Datong Coal Mine Group which mainly exploiting Permo-carboniferous coal seam, with a average distance of 100-300m,The average thickness of carboniferous 3-5# coal seam reach 15 m,belongs to extremely thick coal seam. The two coal seam are both with hard coal and roof condition. Owing to the extremely thick?two-hard and double-system typical mining condition, Tongxin coal mine has come up against problems of large structure vertical failure on the overburden rock and intense strata behavior during the exploiting of Permo-carboniferous coal seam. Therefore, the Research on Overlying Strata fracture characteristics and Mine Pressure Appearance Law about extremely thick coal seam by fully mechanized caving method in Tongxin Coal Ming is the foundation of safety and high-efficient mining for two-hard and double-system coal seam, and is of great importance to good economic and social benefit.Base on the extremely thick two-hard and double-system typical mining condition, this paper applied theoretical calculation and similar material simulation methods to study the relationship between the overburden strata movement and the strata behaviors as a example of 8105 working face.This paper analyzed intense strata behavior of 8105 working face on the basis of that; identified the overlying floor key strata of 8105 working face based on the key strata theory and analyzed fracture step of key strata, floor weighting statistics of 8105 working face meeting the actual situation of the field observation data; simulated the influence of the remain pillars after Jurassic 9#,11#,12#,14#coal seam been exploited to 8105 working face strata behaviors using similar material simulation, verifying the accuracy of theoretical analysis.The study results shows that:Research on Overlying Strata fracture characteristics and Mine Pressure Appearance Law about extremely thick coal seam by fully mechanized caving method in Tongxin Coal Ming offering theoretical basis to strata behaviors of Tongxin coal mine, offering scientific decision support to the prevention of intense strata behavior and owing important theoretical basis coupled with practical application, also offering significant reference to other Permo-carboniferous coal mine in Datong mining area.