Hydraulic support stability control of fully mechanized top coal caving face with steep coal seams based on instable critical angle

Analyzed the support instable mode of sliding, tripping, and so on, and believed the key point of the support stability control of fully mechanized coal caving face with steep coal seams was to maintain that the seam true angle was less than the hydraulic support instability critical angle. Through the layout of oblique face, the improvement of support setting load, the control of mining height and nonskid platform, the group support system of end face, the advance optimization of conveyor and support, and the other control technical measures, the true angle of the seam is reduced and the instable critical angle of the support is increased, the hydraulic support stability of fully mechanized coal caving face with steep coal seams is effectively controlled. Supported by the National Natrual Science Foundation of China(50504014)