Characteristics of Strata Behaviors of Fully Mechanized Top-Coal Caving Face Under Complex Geological Conditions

Based on the complex mining conditions of the 5343 face in No.3 seam of Wulan coal mine,the characteristics of strata behaviors were researched by using the methods of ground pressure observation and numerical simulation.The results show that the first weighting inter-val of roof is 24.2m,and the periodic weighting interval is 9.41m.During the roof weighting,the maximum average support load is 2 775.5kN per frame,with a high sidewise extrusion pressure between supports and a serious rib spalling and roof fall of working face,making the roof control very difficult.Compared with the fully mechanized caving face in ordinary soft coal seam,the strata behaviors of this working face are comparatively severe with a great roof weighting strength and an obvious periodic weighting because of good stability of roof and steep angle of coal seam.