ABSTRACT
In many countries calculation methods have been developed to determine the stability of slopes on or in soil of low bearing capacity. Instabilities usually occur close to the edges of a fill or an excavation. Therefore the equilibrium of the specific mass of ground around these locations must be taken into account. In a stability calculation usually an assumption is made with respect to the plane along which the soil mass may slide, supposing that at each point of that plane the maximum shear stress or shear strength is available. The degree to which this available strength has to be mobilized gives the stability factor SF of that plane. By considering many of these planes the most critical sliding plane with the lowest stability factor SF can be found. In this way the macrostability of slopes can be analysed by trial and error. Over the years numerous computer calculation methods have been developed to determine the least stable sliding plane rapidly and accurately. Especially for less complicated slope situations this relative simple method has proven its great importance and reliability for many decades. However for non-standard situations with complex layer and/or complicated load configurations the traditional method is less suitable. For these cases, finite element programs with a realistic simulation of soil behaviour give better results and certainly are more promising for the future.
