Abstract: In order to improve the ore production of a openpit mine,the slope extension is done by improving slope angle and increasing mining depth, so the high and steep rock slope is formed. The stability of the high and steep rock slope is done, so as to guarantee the safety production of the mine. The FLAC3D software is adopted to conduct simulation analysis, by considering the initial stress state of the slope, the balance calculation is done based on the actual excavation procedures of the slope, the slope excavation procedures is simplified under the principle of from top to down, from outside to inside, so as to analysis the final physical state of the slope. The study results show that, the vertical displacement of the slope is the largest, the horizontal displacement of the slope is the largest, the slope displacement velocity is tend to 0; the maximum principal stress and minimum principal stress are both increased from the top to the bottom of the slope; the shear plastic zone is appeared in the bottom of the slope. The above analysis results further show that, the slope is stable overall, the instability probability of upper rock unstable area is existed; the rock mass is mainly for shear failure, the slope stability can be influence by the shear stress concentration of the bottom of the slope and shallow slope; shear failure is appeared in the bottom of the slope. After the excavation of the slope, it is necessary to take support for the rock mass failure areas, so as to stop the rock mass falling and the inner rock mass falling layer by layer after the slope surface is destructed.

Key words: High and steep rock slope, Maximum principal stress, Minimum principal stress, Shear stress, FLAC3D