One-dimensional consolidation of unsaturated pyroclastic soils: Theoretical analysis and experimental results

This paper synthesizes the results of a study aimed at analyzing the one-dimensional consolidation of unsaturated pyroclastic soils from both theoretical and experimental points of view. In order to pursue this goal, the differential equations governing the problem are firstly derived and their set is solved via the use of the Finite Difference Method. Input data consist of hydraulic and mechanical parameters whereas output data – changing in space and with time – are the settlement, the pore water pressure and the air pressure of the modelled medium. The values of constitutive parameters appearing in the theoretical model are calibrated on the basis of experimental results achieved from laboratory tests carried out, via a suction controlled oedometer, on specimens of unsaturated pyroclastic soils. Considering that consolidation settlements of unsaturated soils are lower than those experienced by the same soils in saturated conditions (changes in boundary conditions being equal), the followed approach – which combines theoretical and experimental results – can be profitably adopted in geotechnical problems in which the quantitative prediction of consolidation settlement values is a requirement of particular concern.