Ricerc@Sapienza

The hydro-mechanical behaviour of a pyroclastic soil layer covering a steep slope has been numerically investigated by performing plane strain analyses using a finite element code. The mechanical behaviour of the volcanic soil has been simulated by means of an elastic-plastic constitutive model extended to unsaturated conditions. The influence of the geometry and soil properties on the slope response has been studied by modifying the slope angle, the permeability law and the water retention curve of the pyroclastic cover.

An experimental study has been carried out to investigate the effects of soil partial saturation on the behaviour of laterally loaded piles. The proposed study has been conducted by means of centrifuge tests at 100×g, where a single vertical pile has been subjected to a combination of static horizontal load and bending moment. The study has been conducted on a silty soil characterized with laboratory testing under saturated and unsaturated conditions. During flight, two different positions of water table have been explored.

This paper concerns the hydromechanical stability of partially saturated soils
during wetting. The response of a loose silty sand is numerically/theoretically
investigated with the main aim of identifying both triggering mechanisms
and predisposing factors to instability. This latter is testified by both a rapid
increase in the pore water pressure and an unexpected loss of numerical
convergence. The study has been conducted at different scales from laboratory
tests to boundary value problems, and in both cases, the controllability theory

This paper presents selected aspects of the model preparation and the experimental procedures used for testing the unsaturated soil behaviour in centrifuge environment. The study is based on the results of centrifuge tests carried out to investigate the influence of partial saturation on the behaviour of laterally loaded piles. The soil used in the experimentation is a high permeability silty clay soil, named B-grade kaolin. The models were statically compacted at two different densities with the same water content.