Research on Sublevel Coal's Failure and Displacement of Extremely Thick Seam's Mining Face

摘要

Based on advancing abutment and displacement's site measurements method, the extremely thick coal seaM mined in 21121 fully mechanized sublevel caving longwall working face of Qianqiu Mine, is studied in detail. It can be seemed from site measurements results that the advancing abutment zone of 21121 working face is longer, and that the interval of top coal can generate apparent abscission layers. On the basis of analysis of these characters, the advancing abutment zone with the maximum scope of 90m is divided into initial compression and plastic deformation zone, strong compression and damage zone, roofs rotation action and supports action zone. Also the sublevel coal with the average thickness of llm above support is divided into roof action layer and short beam structure layer and support's action layer. What's important, the mechanic model of the short beam layer which is vital to successful sublevel mining is built and studied, which can do great benefit to extremely thick coal seams' high efficient mining.