Abstract
For an earth dam located in a narrow canyon, canyon restraint has significant influence on seismic stability of the dam. A numerical method is proposed for slope stability analysis of three dimensional earth dams subjected to horizontal seismic loading. The method is an extension of the simplified Bishop method, taking into account indeterminate shear force acting between vertical slices transverse to the dam axis. Due to the interslice shear force, limit equilibrium can be achieved at all points on a sliding surface. An iterative calculation procedure is presented to determine the magnitude of the interslice shear force and a critical seismic coefficient of the entire dam. Stability analysis by the proposed method is conducted for small-scale earth dam models used in failure experiments, and the analytical results are compared with the observations regarding the seismic coefficient and shape of failure surfaces. The comparison shows a fairly good agreement, demonstrating validity of the method and providing several useful findings concerning the slope stability.
