Stability of slopes in residual soils

Abstract

This paper examines and discusses a number of factors that make slope stability assessments, and slope engineering in residual soils somewhat different from sedimentary soils. In particular, slopes are generally steeper and of higher permeability. They are also likely to be more heterogeneous and thus less amenable to analytical assessment than slopes in sedimentary soils. These factors are discussed in some detail. It is explained that climate and weather influence is much greater in residual soils than sedimentary soils, and theoretical methods are presented for taking this influence into account. It is shown also that traditional computer program methods of slip circle analysis can result in very large errors if applied to steep slopes in which seepage is occurring. More rigorous treatment of the seepage state, especially the "worst case" state is needed in order to produce sensible estimates of safety factor.