In the light of parts of tension-shear yield area inside a rock slope

Hoek-Brown criterion is more suitable for the stability analysis of the rock slope than Mohr-Coulomb criterion because Hoek-Brown criterion can be used to analyze both tension-shear yield and compression-shear yield of the rock slope. Parabola Drucker-Prager criterion based on Hoek-Brown criterion is deduced to get rid of the difficulty which Hoek-Brown criterion is hard to use in numerical analysis. In order to use strength reduction FEM based on parabola Drucker-Prager criterion for the stability analysis of a rock slope

the rationality of reducing material parameters of parabola Drucker-Prager criterion is proved. With these research results

the paper analyses the stability of the slope on the right bank of Cihaxia Hydropower Station under natural and atomization conditions due to spillway discharging. The result indicates that the slope is stable under natural condition

but unstable on atomization condition. Therefore

the engineering measures are necessarily taken to enhance stability of the slope against instability under the atomization condition due to spillway discharging.