Soils used in earth constructions are mostly unsaturated, and they undergo frequent drying-wetting cycles (repeated hydraulic loads) due to changes in climatic conditions or variations of the ground water level, particularly at shallow depths. After compaction, changes in water content can significantly influence the hydromechanical response of the construction material, which therefore has to be assessed for repeated hydraulic loads. This research investigates the effect of such loads on the microstructure and hydraulic behaviour of a silty soil, typically used in the construction of embankments and dykes, with the aim of providing a better understanding of the consequences of drying-wetting cycles on the response of the material over time. Experimental tests were performed to study the impact of drying-wetting cycles on the water retention, hydraulic conductivity and fabric of compacted specimens. Fabric changes are documented to take place even without significant volumetric strains, promoting an irreversible increase in the hydraulic conductivity and a reduction in the capacity to retain water compared to the as-compacted soil. The fabric changes are interpreted and quantified by means of a hydromechanical model, which accounts for the evolving pore size distribution at different structural levels. The proposed model reproduces quite well the microstructural observations, together with the evolution of the water retention behaviour and of the hydraulic conductivity
Effects of repeated hydraulic loads on microstructure and hydraulic behaviour of a compacted clayey silt / Azizi, Arash; Musso, Guido; Jommi, Cristina. - In: CANADIAN GEOTECHNICAL JOURNAL. - ISSN 0008-3674. - STAMPA. - 57:(2020), pp. 100-114. [10.1139/cgj-2018-0505]
Effects of repeated hydraulic loads on microstructure and hydraulic behaviour of a compacted clayey silt
Azizi, Arash;Musso, Guido;
2020
Abstract
Soils used in earth constructions are mostly unsaturated, and they undergo frequent drying-wetting cycles (repeated hydraulic loads) due to changes in climatic conditions or variations of the ground water level, particularly at shallow depths. After compaction, changes in water content can significantly influence the hydromechanical response of the construction material, which therefore has to be assessed for repeated hydraulic loads. This research investigates the effect of such loads on the microstructure and hydraulic behaviour of a silty soil, typically used in the construction of embankments and dykes, with the aim of providing a better understanding of the consequences of drying-wetting cycles on the response of the material over time. Experimental tests were performed to study the impact of drying-wetting cycles on the water retention, hydraulic conductivity and fabric of compacted specimens. Fabric changes are documented to take place even without significant volumetric strains, promoting an irreversible increase in the hydraulic conductivity and a reduction in the capacity to retain water compared to the as-compacted soil. The fabric changes are interpreted and quantified by means of a hydromechanical model, which accounts for the evolving pore size distribution at different structural levels. The proposed model reproduces quite well the microstructural observations, together with the evolution of the water retention behaviour and of the hydraulic conductivityFile | Dimensione | Formato | |
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AA_GM_CJ_2019_Can Geot J_Repeated hydraulic loads hydraulic behaviour of a compacted clayey silt.pdf
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Descrizione: Azizi et a. (2020) Canadian geotechnical journal. Effects of repeated hydraulic loads on the hydraulic behaviour of a compacted clayey silts
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2a Post-print versione editoriale / Version of Record
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https://hdl.handle.net/11583/2759729