Hydromechanical behaviour of overconsolidated unsaturated soil in undrained conditions

Wu, Shengshen; Zhou, Annan; Li, Jie; Kodikara, Jayantha; Cheng, Wen-Chieh

doi:10.1139/cgj-2018-0323

Cited by 13 publications

(3 citation statements)

References 53 publications

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“…While the overconsolidation ratio (OCR) is often used in constitutive modeling of saturated soils, the dual effects of suction on the effective stress and yield stress imply that it is difficult to use this parameter in the interpretation of data. Nonetheless, Wu et al (2019) found that the shear strength of unsaturated sedimented soils depends on the OCR prior to desaturation.…”

Section: Volume Change Of Unsaturated Soilsmentioning

confidence: 99%

Compression Response of Sedimented Unsaturated Soils

Behbehani

McCartney

2022

J. Geotech. Geoenviron. Eng.

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This paper presents an experimental study on the hydro-mechanical behavior of unsaturated sedimented soil to understand the impacts of suction on the apparent yield stress and gain insight into the differences in behavior from compacted soils. A large-strain oedometer was developed for use in a triaxial cell that permits initial sedimentation of soils from a slurry under backpressure, suction control using the axis translation technique, and mechanical loading to characterize the compression curve. A flow pump was used to control the pore water pressure at the base of the soil specimen and to track water flow during suction application and mechanical loading. After initial consolidation of saturated soil specimens from a slurry, the specimens were unloaded, different suction values were applied, then the axial stress was increased to 11 MPa at a constant strain rate. An increase in apparent yield stress with suction was observed, and the compression curves for higher suctions diverged without reaching pressurized saturation in the applied stress range. When compared with compression curves for the same soil compacted dry of optimum presented in previous studies, the sedimented soil had a greater yield stress at saturated conditions but a similar increase in yield stress with suction. Sedimented soils also experienced smaller changes in void ratio with applied net stress and a higher air entry suction value compared to compacted soils, reflecting a more compact soil structure. Suction was found to have a greater impact on yield stress than suction stress for both sedimented and compacted soils.

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Section: Volume Change Of Unsaturated Soilsmentioning

confidence: 99%

Compression Response of Sedimented Unsaturated Soils

Behbehani

McCartney

2022

J. Geotech. Geoenviron. Eng.

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“…However, as stated by Hashiguchi 13 – 15 , classic elastoplastic constitutive models with a single yield surface enclosing the elastic domain possess many limitations in describing the mechanical response of soils. First, the original CASM predicts pure elastic behaviour inside the yield surface while the experimental data show that recoverable deformation only occurs within a very small range 16 – 19 . CASM describes discontinuous variation of the tangent stiffness modulus from elastic to plastic of over-consolidated soils and predicts an unsmooth stress–strain relation, and thus is unable to describe softening behaviour accurately 9 , 17 , 20 .…”

Section: Introductionmentioning

confidence: 99%

Modified unified critical state model for soils considering over-consolidation and cyclic loading behaviours

Wang

Yuan

Cui

2023

Sci Rep

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This paper presents a modified unified critical state model to predict the mechanical responses of both clays and sands under over-consolidation and cyclic loading conditions on the basis of clay and sand model (CASM), which is named as CASM-kII. Through the application of subloading surface concept, CASM-kII is able to describe the plastic deformation inside the yield surface and the reverse plastic flow, and is thus expected to capture the over-consolidation and cyclic loading behaviours of soils. CASM-kII is numerical implemented by the using of the forward Euler scheme with automatic substepping and error control. Then, a sensitivity study is carried out to check the influences of the three new parameters of CASM-kII on the mechanical response of soils in over-consolidation and cyclic loading conditions. Through the comparisons of experimental data and simulated results, it is found that CASM-kII is able to satisfactorily describe the mechanical responses of both clays and sands in over-consolidation and cyclic loading conditions.

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“…For the laboratory testing, large amounts of triaxial tests under different confining pressures, over-consolidated ratios (OCR) and axial strain rates were carried out to analyze the rate-dependent behavior of saturated clays at different initial states. [3][4][5][6] Besides, constant strain tests (CRS) were performed on reconstituted and natural clays in oedometer, allowing a unique relationship among stress, strain and strain rate to be identified. 7,8 The yield stress and shear strength were found to increase with increasing strain rate.…”

Section: Introductionmentioning

confidence: 99%

A viscoplastic constitutive model for unsaturated soils based on nonstationary flow surface theory

Wang,

Cui

2023

Num Anal Meth Geomechanics

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A viscoplastic constitutive model is developed to describe the viscoplastic behavior of unsaturated soils. The proposed model accounts for the stain‐rate and suction effects on yield by adopting an unsaturated isotach concept. The nonstationary flow surface theory (NSFS) is applied for modeling the viscoplastic behavior, with the yield surface which can evolve with the viscoplastic strain, viscoplastic strain rate and suction. Meanwhile, the progressively hardening concept is adopted for reproducing the viscoplastic behavior of soil at an over‐consolidated state. For the validation, a series of loading conditions are considered based on the data from the literature. Results show that the proposed model is able to reproduce the main viscoplastic behaviors of unsaturated highly compacted Gaomiaozi (GMZ) bentonite, Glenroy silt and Qianjiangping landslide (QL) soil, including CRS compression tests, rate‐dependent triaxial shear tests, and triaxial creep tests.

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Hydromechanical behaviour of overconsolidated unsaturated soil in undrained conditions

Cited by 13 publications

References 53 publications

Compression Response of Sedimented Unsaturated Soils

Compression Response of Sedimented Unsaturated Soils

Modified unified critical state model for soils considering over-consolidation and cyclic loading behaviours

A viscoplastic constitutive model for unsaturated soils based on nonstationary flow surface theory

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