Abstract: According to the analysis of the mined slope affected by open-pit and underground mining, the girder model of mined slope was built.Based on the stress and distortion of the girder, the range of arch was drawn out from distortion of girder, which is also called the affected slope range.By analyzing the sinking range formed from broken roof strata, the calculation of stabilization coefficient of mined slope and the most safety mining depth were obtained.Combining with the practice of open-pit and underground mining and the displacement survey of slope in Anjialing open pit, the slope stabilization coefficient was 1.38 and the most safety mining depth was 309 meters at the 902 working face.The research indicated that the distortion of mined slope under open-pit and underground mining was drawn from strata angle alter evoked from ceiling distortion, providing the theoretical foundation to keep the stability of mined slope under open-pit and underground mining.  

Key words: Open-pit and underground mining, Mined slope, Girder model, Stability