Target reliability indices for long geotechnical embankment slopes

Abstract

The target reliability indices of earth embankment slopes were investigated using a proposed segmentation-based method. First, an embankment is equally segmented into multiple embankment sections. The total number of sections is determined based on the potential number of discrete failures along the embankment. Then, for two types of engineering embankment, the series system and the k-out-of-n system are used to model the relationship between section reliability and embankment system reliability. Finally, section target reliability indices are derived based on two embankment reliability requirements, which are described by the design failure ratio (the ratio of the allowed section failure number to the total section number) and system target reliability index. The results indicate that the total embankment length and soil variability significantly affect the section target reliability index, and different section target reliability indices may be required for different embankment projects. These effects were appropriately incorporated into the derivation of a section target reliability index in this work, and design charts are provided. Compared with the series system model, where no section failure is allowed, the k-out-of-n system model can provide more-economical design plans by accepting a small design failure ratio.