Abstract: With the rapid development of mountain highways, the problem of high slope stability caused by them also needs to be solved urgently. After excavation, the safety factor of the slope will be reduced, and the slide may occur at any time. Therefore, the stability of the slope after excavation should be evaluated before excavation and dynamically designed to prevent landslides. Based on a highway in Sichuan, the Mohr-Coulomb model is used to analysis the safety factors of the slope before and after excavation by using Geostudio and FLAC3D numerical simulation. The safety factor under different methods is compared, and the maximum horizontal displacement, shear strain increment and shear stress of the slope before and after excavation are analyzed. Finally, the support suggestions for the slope are proposed. The results show that after the slope is excavated, the stability is reduced, and if it encounters extreme conditions such as earthquakes and heavy rains, the safety factor may be reduced again, and there is a risk of instability, so it should be supported in time. 

Key words: Strength Reduction Method, Limit Equilibrium Method, Factor of Safety, Stability, Slope Support