TY - JOUR
T1 - Hydromechanical behaviour of two unsaturated silts
T2 - laboratory data and model predictions
AU - Bruno, Agostino Walter
AU - Gallipoli, Domenico
AU - Mendes, Joao
PY - 2022/6/1
Y1 - 2022/6/1
N2 - This paper presents the results from a campaign of unsaturated and saturated isotropic tests performed on two compacted silts of different coarseness, namely a clayey silt and a sandy silt, inside triaxial cells. Some tests involved an increase or a decrease of mean net stress at constant suction or an increase or a decrease of suction at constant mean net stress. Other tests involved an increase of mean net stress at constant water content with measurement of suction. During all tests, the void ratio and degree of saturation were measured to investigate the mechanical and retention behaviour of the soil. The experimental results were then simulated by the bounding surface hydromechanical model of A.W. Bruno and D. Gallipoli (2019. Computers and Geotechnics, 110: 287–295. doi:10.1016/j.compgeo.2019.02.025), which was originally formulated to describe the behaviour of clays and clayey silts. Model parameters were calibrated against unsaturated tests including isotropic loading stages at constant water content with measurement of varying suction. Loading at constant water content is relatively fast and allows the simultaneous exploration of large ranges of mean net stress and suction, thus reducing the need of multiple experiments at distinct suction levels. Predicted data match well the observed behaviour of both soils, including the occurrence of progressive yielding and hysteresis, which extends the validation of this hydromechanical model to coarser soils. Specific features of the unsaturated soil behaviour, such as wetting-induced collapse, are also well reproduced.
AB - This paper presents the results from a campaign of unsaturated and saturated isotropic tests performed on two compacted silts of different coarseness, namely a clayey silt and a sandy silt, inside triaxial cells. Some tests involved an increase or a decrease of mean net stress at constant suction or an increase or a decrease of suction at constant mean net stress. Other tests involved an increase of mean net stress at constant water content with measurement of suction. During all tests, the void ratio and degree of saturation were measured to investigate the mechanical and retention behaviour of the soil. The experimental results were then simulated by the bounding surface hydromechanical model of A.W. Bruno and D. Gallipoli (2019. Computers and Geotechnics, 110: 287–295. doi:10.1016/j.compgeo.2019.02.025), which was originally formulated to describe the behaviour of clays and clayey silts. Model parameters were calibrated against unsaturated tests including isotropic loading stages at constant water content with measurement of varying suction. Loading at constant water content is relatively fast and allows the simultaneous exploration of large ranges of mean net stress and suction, thus reducing the need of multiple experiments at distinct suction levels. Predicted data match well the observed behaviour of both soils, including the occurrence of progressive yielding and hysteresis, which extends the validation of this hydromechanical model to coarser soils. Specific features of the unsaturated soil behaviour, such as wetting-induced collapse, are also well reproduced.
KW - Unsaturated soils
KW - Hydromechanical behaviour
KW - bounding surface plasticity
KW - unsaturated triaxial testing
KW - collapse-compression
UR - http://www.scopus.com/inward/record.url?scp=85131219688&partnerID=8YFLogxK
U2 - 10.1139/cgj-2021-0170
DO - 10.1139/cgj-2021-0170
M3 - Article
VL - 59
SP - 837
EP - 846
JO - Canadian Geotechnical Journal
JF - Canadian Geotechnical Journal
SN - 0008-3674
IS - 6
ER -