Abstract
Seepage forces computed by a finite-element flow program are combined with gravity forces in an elastic-plastic stress-analysis program to determine the stability of mine-waste slopes. Computer output provides a cross-sectional plot of the dam or embankment showing the safety factors for each element. The combined finite- element program called seep-slope was used to analyze several trial embankments and the 1972 Buffalo Creek dam failure. Safety factors computed by the finite-element method (fem) were compared with those computed by bishop limiting-equilibrium method. For individual slip circles, there was little correlation between the factors of safety computed by the two methods. Both predict failure, but fem shows a different mode of failure plus development of potential failure zones not indicated by conventional methods. Besides having a better theoretical basis than the bishop method, fem requires no assumptions regarding the location or geometry of the failure surface. As a result, the program will show progressive development of a failure zone, and areas can be pinpointed where remedial measures should be taken. In addition, nonhomogeneous cross sections can be analyzed, and zones of potential piping can be defined.
