Abstract: Potentially unstable rock mass is generally in unsteady or limit equilibrium state. There are many factors (that affect the stability of potentially unstable rock mass, but geological exploration is often difficult to give accurate parameters about the potentially unstable rock mass. With the potentially unstable rock mass at Huashi cliff on Jinsha River as an example, we took in consideration factors including crack position and depth, fissure water pressure, strength parameters of potentially unstable rock mass, and parameters of weak rock strata under the potentially unstable rock mass. Furthermore, we calculated the effect of the above factors on the safety coefficient of rock mass by using FLAC^3D based on strength reduction method. Through comparisons, we concluded that fissure water pressure and parameters of weak rock strata under the potentially unstable rock mass have great influence on the stability of the potentially unstable rock mass. Therefore, weak rock strata under the potentially unstable rock mass should be reinforced, and the fissures must be closed to prevent from rainwater collection.

Key words: Key words: treatment of potentially unstable rock, instability and failure, strength reduction method, influence factor, FLAC^3D