Influence of Seepage on Stability of Sandy Slope

Abstract

The influence of seepage on the stability of a sandy slope is investigated. Two failure modes that influence the slope stability can be distinguished. A `continuum' mode if an outward flow is present and a `single particle' mode for an inward flow. A description of these two failure modes is presented and compared with the results of experiments. The description of the continuum mode is based on well known continuum soil mechanics, the single particle mode is based on elaborating the momentum equation for one single sand particle. The single particle mode results in a lower stability than could be expected when using the continuum mode. In the experiments the stability of a sandy slope was tested for different slope angles and hydraulic gradients. In these experiments the difference between the two failure modes was clearly present and the transition between stable and unstable slope was in agreement with theory.