Abstract: Under the influence of fault and rock joints, the local rock slope failures at south portion of Jinduicheng Mine are frequently occurred. The failure modes include rock sliding, rock burst and rock fall. The lithology of the south bank of the rock slope consists of quartzite, slate and Anshan siltstone. The stability of rock slopes in different rock lithology is significantly different. Based on the geotechnical investigation result for the rock slope, the rock slope stability of south portion was evaluated using stereographic projection method and the potential locations of the instability of these rock slopes were predicted. The quartzite rock slope is mainly encountered in the west side. The single step sliding failure mode was identified by L1 structural plane. The combination of rock joints of L1 and L2 would lead to a wedge failure mode. The middle portion of slope consists of slate rock. The joint L1 is daylighting with the rock slope at a small angle so that the sliding failure potential existed. The Anshan siltstone rock slope is found at the east portion. The L2 joint set is less than the slope angle of the step so that the broken siltstone at the surface sliding failure might be occurred along this plane.

Key words: rock slopes, stability, structural plane, stereographic projection