Abstract: According to the support inclining problem in southern of upper 7240 working face in Renlou coal mine, this paper analyzes the reason of support inclining from the angle of ground pressure, water inflow and mining velocity. The results showed that roof leaking leads to a slow mining velocity. Using frequent turning mining to keep advancing results in stress raisers in the area of machine tail and uneven stress of top beam, additionally the machine tail supports were under high load as the result of roof weighting, and then the bottom of supports sunk and lost their balance, gradually sunk into floor which are softened by water, then the whole body of supports lost their balance, finally lead to supports inclining at working face. Propose the prevention measures of supports inclining according to the specific conditions of upper-7240 southern working face.

Key words: support inclining, periodic weighting, turning mining, support sink