Research On The Movement Behavior Of Overburden In Large Inclined Angle Face

Based on the research achievement of steeply dipping seam mining is put forward recently, and combinates with mining geological condition of the 115011 working face. Theoretical analysis, physical simulation, numerical simulation and field measurement are conducted to analyze the movement behavior of overburden in steeply dipping seam mining face. The main research results are as follows:(1) The whole overburden arch structure is like "7" type after the large inclined angle working face is mined. Each hierarchical caved and accumulated to the overburden arch structure, broken roof hinged structure mechanics model is set up, analysis stress of the structure, and put forward its instability condition.(2) The vertical stress distribution is "asymmetry" along the working face tendency, vertical stress is small in the upper area of working face, and exist stress release area, but in the lower area of working face the vertical stress is concentrated. Influenced by coal seam dip angle, abutment pressure in the upper area of steeply dipping seam mining face is lesser, the central area is larger, the lower area is biggest; The abutment pressure peak value at close range from the working face in the upper area, the central times, lower the farthest; The stress concentration coefficient in the middle area is biggest, the upper area is second, the lower area is minimum.Zero stress area, low stress area and stress disturbed area will formatted after the steeply dipping seam mined, and zero stress zone range is become smaller and closer to the upper area.(3) Field observations show that, first weighting interval of 115011 working face is 43.2 m, the average support working resistence during first weighting is 5052 k N. periodic weighting interval of 115011 working face is 17.3 m, the average support working resistence during periodic weighting is 4149 k N. Support working resistance in the upper-middle area is bigger, in the bottow area is smaller, and the dynamic load coefficient is bigger. The rear support working resistance significantly greater than the front. “Support-Surrounding-Rock”mechanical structure model is established, The critical dumping angle of 115011 working face is 23.2°, the critical slip angle is 7.4°.