Abstract: Geological conditions of Yunnan Plateau are very complicated. Land resources are limited, and engineering hazards associated with the fill embankments are frequently encountered. The geotechnical investigation for the proposed Highway Bridge No.1 at Baiyan Village in Kangzheng to Gengma Expressway project indicated that unfavorable subsurface conditions, such as soft soils and karst rock cavities, were encountered at the proposed bridge substructure locations. A fill embankment was selected to replace the proposed bridge. The global stability of the fill embankment would determine whether this approach can be implemented. The stability of the fill embankment above the unfavorable karst rock cavities and pinnacles under various loading conditions were analyzed with Bishop method. It is concluded that the presence of the karst geology has an adverse impact on both the global and local stabilities. The proposed embankment would be stable after the appropriate ground improvement.

Key words: expressway, embankment fills, global stability, local stability, settlement and deformation