Small- and full-scale test programme on uplift induced slope failure

Abstract

Sub soil stratum in deltaic regions typically include a succession of permeable and non-permeable layers. Consequently, dikes built to protect delta areas, should be able to resist not only extreme surface water levels, but also an increase in hydraulic head in permeable layers. The rise in hydraulic head might result in uplift of the cover layer, inducing either backwards erosion piping or slope stability. A large research programme, including the combination of numerical analysis, centrifuge testing and field trials, is started to study the uplift phenomenon. Preliminary results show that uplift has a clear influence on dike stability. Horizontal compression of the cover, during uplift, might trigger slope failure. Large cracks in uplifted cover layer were not found in the field trials, although some local failure, resulting in sand boils, was observed. The test results provide valuable experimental data to further validate numerical tools and stability assessment procedures.