Abstract: Based on the measured results of ground pressure in No. 22303 working face of Bulianta Coal Mine, Shendong mining area, the strata behaviors in different stages of the first 7.0m height fully-mechanized face around the world are summarized in this paper, and combining with the strata behaviors in various fully-mechanized faces of Shendong mining area, the differences of various fully-mechanized faces are comparatively analyzed in detail. The results show that the strata behavior of 7.0 m support fully-mechanized face remains regular when mining under the overlying coal pillars, but when nearly mining out of the pillar area, the coal wall caves, largely which directly leads to the crushing death of the scraper conveyor. While mining under the long wall goaf, the strata behavior of single key stratum structure in 7.0 m fully-mechanized face differs from that in double key strata structure. Within the single key stratum structure, the nearer the key stratum structure to the coal seam is, the larger the parameters of strata behavior are (except the roof weighting step), while within the double key strata structure, the roof weighting step and dynamic load coefficient present periodical alternating changes, and the large roof weighting step comes along with the small dynamic load coefficient. Through comparing the strata behaviors between 7.0 m fully-mechanized face and several other fully-mechanized faces in Shendong mining area, we conclude that the higher the mining height is, the larger the support strength is, and the smaller the dynamic load coefficient is. In addition, the higher the mining height is, and the nearer the first inferior key strata to the coal seam is, it is more easier to form “cantilever” structure in the first inferior key strata, so as to lengthen the roof weighting.

Key words: shallow seam；7.0 m height support；strata behavior；key strata；“cantilever&rdquo, structure