Inundation collapse strain and creep measurements for two Campanian pyroclastic soils

Collapsible soils are characterized by a loose metastable texture causing their collapse to a stable denser state upon wetting. In this paper measurements of collapse strains of two Campanian (Southern Italy) pyroclastic soils by the single oedometer test technique (ASTM D 5333) are presented. The time evolution of strain is analyzed, recognising a capillary rise phase followed by creep. It is shown that both phases can be represented by a power law, the end of capillary rise (EOCR) time separating the two phases being calculated. Pre-inundation and collapse strains are finally expressed in terms of a void index (Burland 1990), using saturation as the reference state.