Collapse upon wetting of lime stabilised pyroclastic soils

Compacted soils are commonly used in the construction of geotechnical works such as road embankments and earth dams. Several investigators have highlighted the wetting-induced behaviour of compacted soils resulting in collapse of the soil skeleton with increase of volume strains. The addition of lime, with the subsequent physic-chemical reactions, generally reduces the collapse potential of the stabilised soil if compared to the not treated one. In the paper, soil collapse has been investigated by means of soaking tests under constant stress on reconstituted not treated and lime stabilised pyroclastic soils. The soil collapse has been analysed for stress levels corresponding to pre-yield, yield and post-yield condition. The experimental results show the relevant dependency of the collapsible behaviour on the initial state of the compacted samples (void ratio, water content), the treatment parameters (curing time) and the reference stress level.