Abstract: With the increase of excavation depth in open-pit mines, in-situ stress becomes an important factor affecting slope stability. Based on improved Spencer method, the formulas and program of three-dimensional LEM under horizontal geo-stress have been established and used in the slope of Shuichang open-pit mine. The numerical simulation results, using FLAC3D based on strength reduction method and the in-situ monitoring data of the slope, have been used to compare with the results of LEM. Studies show that the factors of safety under horizontal geo-stress by LEM and numerical simulation method are smaller than that without geo-stress, but the slip masses are bigger. Displacements under horizontal geo-stress gotten by numerical simulation are closer to the values from field monitoring. Therefore, the impact of geo-stress must be considered for stability analysis on deep-concave slopes.

Key words: slope stability, geo-stress, three-dimensional limit equilibrium method, factor of safety, numerical simulation