Abstract:
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Experimental data from different testing methodologies on different compacted clayey soils, with dominant bimodal pore size distribution, are presented and analysed, to
provide a comprehensive picture of the evolution of the aggregated fabric along hydraulic and mechanical paths. Fabric changes are analysed both from the porous network viewpoint, by means of careful mercury intrusion porosimetry investigation, and from the soil skeleton viewpoint, by quantifying swelling and shrinkage of the
aggregates in an environmental scanning electron microscopy study. The consequences of the aggregated fabric evolution on the water retention properties of compacted
soils are analysed and discussed. A new model for water retention domain is proposed, which introduces a dependence
of the intra-aggregate pore volume on water content.
The model succeeds in tracking correctly the
evolution of the hydraulic state of the different soils investigated along generalised hydromechanical paths.
The proposed approach brings to light coupling between intra-aggregate and inter-aggregate pores in the retention properties of compacted clayey soils. Dependence of the
air entry and the air occlusion values on swelling and shrinking of aggregates, besides void ratio, is introduced and discussed. |