Hydromechanical behaviour of two unsaturated silts: laboratory data and model predictions

Bruno, Agostino Walter, Gallipoli, Domenico and Mendes, Joao (2021) Hydromechanical behaviour of two unsaturated silts: laboratory data and model predictions. Canadian Geotechnical Journal. ISSN 0008-3674 (In Press)

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Official URL: https://doi.org/10.1139/cgj-2021-0170

Abstract

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/decrease of mean net stress at constant suction or an increase/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 Bruno and Gallipoli (2019), 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.

Item Type: Article
Uncontrolled Keywords: Unsaturated soils, Hydromechanical behaviour, bounding surface plasticity, unsaturated triaxial testing, collapse-compression
Subjects: F600 Geology
F800 Physical and Terrestrial Geographical and Environmental Sciences
H900 Others in Engineering
Department: Faculties > Engineering and Environment > Mechanical and Construction Engineering
Depositing User: Rachel Branson
Date Deposited: 02 Aug 2021 10:07
Last Modified: 30 Sep 2021 16:15
URI: http://nrl.northumbria.ac.uk/id/eprint/46819

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