Including degree of capillary saturation into constitutive modelling of unsaturated soils

Zhou, Annan; Wu, Shengshen; Li, Jie; Sheng, Daichao

doi:10.1016/j.compgeo.2017.09.017

Cited by 64 publications

(21 citation statements)

References 68 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The classic BBM model is based on net stress and suction whereas a few others use an effective stress and suction [14,15,31]. Some recently appeared models proposed to use the degree of saturation instead of suction as a generalised stress variable [32][33][34]. This new approach seems to be promising, but the feedback is still limited.…”

Section: Partial Saturation and Effective Stressmentioning

confidence: 99%

Modelling the poroplastic damageable behaviour of earthen materials

Wong

Fabbri

et al. 2018

Mater Struct

View full text Add to dashboard Cite

This paper presents a new constitutive model on the poroplastic behaviour of earthen materials accounting for stiffness degradation, using the approach of continuum damage mechanics. The poroplastic behaviour is modelled based on the bounding surface plasticity (BSP) theory and the concept of effective stress while isotropic damage is modelled using a scalar variable. Plastic flow and damage evolution occur simultaneously in a coupled process which take into account the impact of suction. The model was successfully validated against results of triaxial compression tests performed at different relative humidities and confining pressures. Despite the relatively small number of material parameters, this model can reproduce the essential features of earthen materials behaviour observed experimentally: suctioninduced hardening and stiffening, post-peak softening, as well as the progressive transition from contractant to dilatant volumetric behaviour. Use of the BSP theory allows to reproduce a smooth stress-strain relation as experimentally observed, instead of an abrupt change upon plastic yielding predicted by classic elastoplastic models. Furthermore, the present model also furnishes a quantitative description on the degradation of elastic properties hitherto not accounted for, thanks to the additional scalar damage variable. Keywords Unsaturated rammed earth Á Bounding surface plasticity Á Suction Á Damage Á Degradation The original version of this article was revised due to a retrospective Open Access order.

show abstract

Section: Partial Saturation and Effective Stressmentioning

confidence: 99%

Modelling the poroplastic damageable behaviour of earthen materials

Wong

Fabbri

et al. 2018

Mater Struct

View full text Add to dashboard Cite

show abstract

“…A simplex fractal dimension is usually used to describe the PSD of soil, and this fractal parameter can be used as a constant in models of soil-water characteristic curves (SWCCs) or particle crushing [33,[42][43][44][45][46][47]. However, according to the data in this paper and other relevant literatures [18,48], a simplex fractal dimension sometimes does not adequately describe the fractal characteristics of the whole PSD.…”

Section: Fractal Patternmentioning

confidence: 95%

Fractal Pattern of Particle Crushing of Granular Geomaterials during One-Dimensional Compression

Zhang

2018

Advances in Civil Engineering

View full text Add to dashboard Cite

This paper focuses on the effect of particle crushing on the behavior of granular geomaterials. Series of high-pressure one-dimensional compression tests were carried out on a quartz sand-gravel. A detail investigation was performed primarily on the compression behavior, the evolution of particle-size distribution (PSD), the fractal pattern of the grading curve, and the amount of particle crushing. It was found that both the yielding state and the state at the maximum compressibility are closely associated with the evolution of PSD and the fractal pattern of particle crushing. As the vertical stress increases, the fractal characteristic of the grading curve appears only within the finer part at first, evolves into bifractal within the overall measurable grading curve late, and translates into monofractal finally. Furthermore, a pair of particle crushing indexes Be1 and Be2 considering different particle size scales were proposed. The reasonability of using Be1 and Be2 to describe the amount of crushing corresponding to the scale of particles was discussed. Finally, it was found that the value of the ratio between the volumetric strain and the crushing index Be1 is constant and independent of the initial particle size and the initial PSD when the vertical stress is larger than the stress at the maximum compressibility or the coarser part of the grading curve is evolved into fractal.

show abstract

“…That is, its current state is dependent on the history of wetting and drying cycle, making its modeling highly challenging, and it is still an ongoing research. [63][64][65][66][67] Here, we shall not attempt its modeling and will assume that an experimentally obtained S w (p c ) curve is provided. (See Section 6 for further discussion.)…”

Section: Analysis Of Volumetric Strainmentioning

confidence: 99%

“…There is a large amount of literature dealing with the theoretical, experimental, and computer simulation aspects of such phenomenon, and we cite only a few here. 66,67,80,84,98,99 As our intention is to develop a linear model based on a small incremental perturbation from a current state, we do not attempt to model the hysteresis phenomenon. We shall assume that we are at a given state, however it is reached.…”

Section: Internal Energymentioning

confidence: 99%

A linear constitutive model for unsaturated poroelasticity by micromechanical analysis

Cheng

2019

Num Anal Meth Geomechanics

View full text Add to dashboard Cite

This paper extends the Biot theory of poroelasticity from the saturated to unsaturated case. The Biot phenomenological model uses parameters that are easily observable, such as the deformation of porous frame, total stress, pore pressure, and fluid specific discharge. Such model is preferred for engineering applications. At this macroscopic level, the extension of Biot theory from saturated to unsaturated is straightforward. The constitutive constants, however, are combined properties of solid, pore space, and fluids. In the unsaturated case, the constants are functions of the degree of saturation. Their measurements and tabulation over a range of saturation is generally not feasible for practical applications. In this work, a Biot-Willis type analysis is performed for the unsaturated case to provide a theory that the bulk material constants can be evaluated using laboratory measurable micromechanical constants under saturated condition, plus a capillary pressure curve (saturation versus suction pressure) typically available for unsaturated porous medium, without the need of measurement at each state of saturation. In particular, it is demonstrated that the surface energy contained in the meniscus interface manifests as a "capillary modulus," given by the negative inverse slope of the capillary pressure curve. A rigorous analysis based on the thermodynamic variational energy approach is also conducted to lend theoretical support to the phenomenological approach. The presented model can bring a closure to the practical engineering modeling of the deformation of partially saturated porous medium that lacks the information of material constants over the range of saturation.

show abstract

Including degree of capillary saturation into constitutive modelling of unsaturated soils

Cited by 64 publications

References 68 publications

Modelling the poroplastic damageable behaviour of earthen materials

Modelling the poroplastic damageable behaviour of earthen materials

Fractal Pattern of Particle Crushing of Granular Geomaterials during One-Dimensional Compression

A linear constitutive model for unsaturated poroelasticity by micromechanical analysis

Contact Info

Product

Resources

About