Elastoplastic soil constitutive laws generalized to partially saturated states

Bolzon, Gabriella; Schrefler, B. A.; Zienkiewicz, O. C.

doi:10.1680/geot.1996.46.2.279

Cited by 301 publications

(199 citation statements)

References 6 publications

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“…Several similar stress frameworks are reported in literature (e.g. [43]) but noticeable differences then appear in choice of complementary stress variable , Equation (25). Due to the simplicity of its formulation, the Bishop generalized effective stress alone is not able to include advanced effects of partial saturation.…”

Section: Effective Stresses Of Categorymentioning

confidence: 61%

Effective stress concept in unsaturated soils: Clarification and validation of a unified framework

Nuth¹,

Laloui²

2007

Num Anal Meth Geomechanics

431

243

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SUMMARYThe effective stress principle, conventionally applied in saturated soils, is reviewed for constitutive modelling purposes. The assumptions for the applicability of Terzaghi's single effective stress are recalled and its advantages are inventoried. The possible stress frameworks applicable to unsaturated soil modelling are reassessed in a comparative manner, specifically the Bishop's single effective stress, the independent stress variables approach and the generalized stress framework. The latter considerations lead to the definition of a unified stress context, suitable for modelling soils under different saturation states. In order to qualify the implications brought by the proposed stress framework, several experimental data sets are re-examined in the light of the generalized effective stress. The critical state lines (CSLs) at different saturation states tend to converge remarkably towards a unique saturated line in the deviatoric stress versus mean effective stress plane. The effective stress interpretation is also applied to isotropic paths and compared with conventional net stress conception. The accent is finally laid on a second key feature for constitutive frameworks based on a unified stress, namely the sufficiency of a unique mechanical yield surface besides the unique CSL.

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Section: Effective Stresses Of Categorymentioning

confidence: 61%

Effective stress concept in unsaturated soils: Clarification and validation of a unified framework

Nuth¹,

Laloui²

2007

Num Anal Meth Geomechanics

431

243

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“…In the present study, the skeleton stress, which has been used recently to analyze multiphase materials within the concept of the mixture theory (Oka et al, 2008(Oka et al, , 2010) is equivalent to those by Bolzon et al (1996), Jommi (2000), and Ehlers et al (2004), etc. The skeleton stress is derived from the natural extension of the eŠective stress for saturated soil and is determined as the diŠerence between the total stress and the average pore pressure as follows:…”

Section: Stress Variablesmentioning

confidence: 98%

Monotonic and Cyclic Behavior of Unsaturated Sandy Soil Under Drained and Fully Undrained Conditions

Kimoto

Oka

Fukutani

et al. 2011

Soils and Foundations

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Changes in air pressure during monotonic and cyclic loading are in some cases important for the behavior of unsaturated soil. For example, in order to investigate the stability of embankments and slope failure during earthquakes, it is necessary to consider the eŠect of the pore air or the pore gas pressure as well as the pore water pressure and the interaction between the soil and the pore ‰uids. In the present study, we carried out a series of monotonic and cyclic loading tests on sandy soil used for the improvement of river embankments. The eŠects of the initial suction, the conˆning pressure, and the degree of compaction under fully undrained conditions, namely, constant water and constant air shearing tests, as well as under drained conditions for both air and water, were studied. For the stress variables of the unsaturated soil, the skeleton stress was used to describe the experimental results and was deˆned as the diŠerence between the total stress tensor and the average pore pressure of water and gas (Oka et al., 2010). From the monotonic and cyclic test results, we found that the stress-strain behavior of unsaturated sandy soil strongly depends on the initial suction, especially under fully undrained conditions, due to the diŠerence in pore pressures. In the cyclic loading tests under fully undrained conditions, the mean skeleton stress decreased due to the increase in air pressure and led to the failure of the specimen in the case of a lower level of initial suction. In addition, the test results exhibited the strain rate eŠect on the stress-strain behavior during cyclic loading under fully undrained conditions.

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“…This gives a different weighting function from that used by Bolzon et al (1996), where the degree of saturation was used. This latter combined stress is referred to as Bishop's stress by Bolzon et al or the average soil skeleton stress by Jommi (2000).…”

Section: Authors' Replymentioning

confidence: 99%