TY - JOUR
T1 - Effects of repeated hydraulic loads on microstructure and hydraulic behaviour of a compacted clayey silt
AU - Azizi, Arash
AU - Musso, Guido
AU - Jommi, Cristina
N1 - Publisher Copyright:
© 2020, Canadian Science Publishing. All rights reserved.
PY - 2020/1/1
Y1 - 2020/1/1
N2 - Soils used in earth construction projects 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 must 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 hydraulic conductivity.
AB - Soils used in earth construction projects 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 must 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 hydraulic conductivity.
KW - Compacted silt
KW - Drying-wetting cycle
KW - Hydraulic conductivity
KW - Hydromechanical model
KW - Microstructure
KW - Water retention
UR - http://www.scopus.com/inward/record.url?scp=85077495567&partnerID=8YFLogxK
UR - https://dro.dur.ac.uk/
U2 - 10.1139/cgj-2018-0505
DO - 10.1139/cgj-2018-0505
M3 - Article
AN - SCOPUS:85077495567
SN - 0008-3674
VL - 57
SP - 100
EP - 114
JO - Canadian Geotechnical Journal
JF - Canadian Geotechnical Journal
IS - 1
ER -