Abstract：The problems of strata behaviors and ground control have been focused by fully-mechanized coal face with sublevel caving in Gengcun coal mine. Based on the geological and mining conditions of the coal face in Gengcun coal mine of Yima mining area, Henan, China, the laws of overlying strata movement and strata behaviors at coal face were studied with methods of numerical simulation and strata pressure field observation. The results showed that: ( 1) The voussoir beam structure of“three hinged-arch”was formed in basic roof above the coal face. The initial instability and periodic instability of the structure caused the initial weighting and periodic weightings at the coal face. The abutment pressure in front of the coal face tended to be stable after basic roof weighting, which manifested that the maximum stress concentration coefficient and the plastic zone range were basically unchanged. ( 2) The periodic weighting interval of basic roof at the coal face was 14. 4 ~ 17. 5 m, with an average 16. 2 m. The dynamic coefficient of basic roof weighting was 1. 81 ~ 2. 04, with an average of 1. 92.Roof weightings were obvious, but more moderate. During the roof weighting at the coal face, the time-weighted average working resistance of supports was about 72. 2% of their rated working resistance. So, using the ZF8600/18/35D caving supports was reasonable. The conclusions provided technical supports for grounding control of fully-mechanized mining with sublevel caving in Yima mining area.

Keyword：extremely-thick coal seam;fully mechanized mining with sublevel caving;strata pressure behavior;overlying strata movement and deformation;