Abstract: Landslides, debris flows, and other geological hazards induced by the spoil sites of mountain expressways were frequently occurred, which have become a serious safety concern in the highway construction. Therefore, to analysis and evaluate the stability of the spoil sites have engineering significance. A spoil site, which is on the 40 meters left at Station K65+000 of an Expressway in Guizhou Province, was presented as a case study. The stability of this spoil site was evaluated based on the field and laboratory geotechnical investigations and the limit equilibrium of rigid body method. The results indicate that, the spoil site was stable under various conditions include heavy precipitations. Other engineering recommendations, such as, improve the drainage system at the spoil site and cover the entire site with grass, are also proposed in the paper.

Key words: mountain expressway, spoil sites, field investigation, stability analysis