Water retention behaviour of an embankment model

Abstract

The depth of the unsaturated zone is strongly influenced by environmental factors. Approximately two-thirds of the world has sufficiently hot or arid climatic conditions so that the unsaturated zone forms more than a very shallow surface layer. Moreover, even in regions where unsaturated conditions are limited to a shallow surface layer; many practical problems in geotechnical engineering (i.e. slope stability, pollutant migrations) are significantly affected by the hydro-mechanical processes occurring in the unsaturated zone. Soil is used extensively as a fill material (i.e. earth-works such as road, railway and flood embankments, earth dams or behind retaining structures) and the unsaturated condition of the fill will crucially affect its behaviour. Seasonal variations in climatic conditions affect the water retention in soils; as a result they swell and shrink. During the dry spells the shrinkage of soils is commonly associated with the formation of cracks. This work presents preliminary results related to the analysis of a scaled flood protection embankment subjected to drying and wetting processes. The evolution of the unsaturated state of the fill under changes in the environmental conditions is explored and the potential influence of desiccation cracks in the soil mass is analyzed in this work.