Research on key technology of powered support design in 8.2 m large mining height face

Based on summarizing the experience of using of fully-mechanized mining equipment, powered support in 8. 2 m ultra large mining height working face was researched; stability of powered support, preventive measures of spalling, impact resistance, coordination method and weldability of the new material were studied; in stability angle of powered support and effect of pin-hole on stableility were calculated; the three level coordinated coal wall protector was optimized; large diameter i mpact resistant pillar was developed; assembled forging pillar socket was designed; coordination method in 3.5 m working face was solved; new material Q890 was res earched and whose weld ability was experimented meanwhile; the stableility and relability of ultra large height powered support were solved and the powered support was lighter in the premise of the enough support structural strength, the coal recovery rate was improved.