Abstract: Instabilities are prone to be induced under the blast loading for the high rock cut slopes in open pit mines. An improved method, which considering the frequency effect of the seismic inertia, is used in the time history analysis of the rock slope stability under the blast load. Combined with kinematical method, limit equilibrium method and numerical method, a comprehensive evaluation method for the cut slope stability was proposed. The improved method was applied to evaluate a rock slope of a tungsten mine. The results show that the higher the vibration frequency is, the more the safety factor decreases. But the higher the vibration frequency is, the faster the dynamic response attenuates and the extent of the safety factor reduction is limited. The time history curve of the safety factor of planar and wedge failure calculated by limit equilibrium method fluctuates around the static safety factor. The minimum value of the safety factor is 1.3, which is in accordance with the results of the FEM method. All of these indicate that the general failure of the slope is unlikely, but toppling or rockfall failure of small scale is probable.

Key words: High Rock Slopes, Blasting Vibrations, Improved Time History Analysis, Comprehensive Evaluations