Abstract: The study on stability and failure mode of anchorage rock masses is the foundation of the ultimate bearing capacity evaluation. The integrations of numerical simulation and in situ scale model test are believed to be an effective and convenient method to achieve our study purpose. As an example, this method is carried out in stability and failure mode analysis of Balinghe super bridge. According to the FLAC3D numerical analysis, the stress field and displacement field show subsection characters under designed load. There are some stress concentration and excessive displacement zones at the corners of the structure and the upper part of the hollow anchorage room. There is no coherent plastic zone in the anchorage-rock mass system. Some partial failure zones mainly appear in five areas including the upper-right of the anchorage. According to the overload test, the failure does not simply happen on the boundary of the anchorage and rock masses, but holding the surrounding rock appears as plug style tensile-shear complex failure. The numerical calculated results coincide well with the in-situ scale model test. The plastic and prominent deformation zones in the rock mass should be paid more attention during design and construction.

Key words: tunnel-anchorage, stability, failure mode, scale model test