Unsaturated permeability of Gaomiaozi bentonite under partially free-swelling conditions

Niu, Wenjie; Ye, Weimin; Song, Xiaoyu

doi:10.1007/s11440-019-00788-9

Cited by 33 publications

(10 citation statements)

References 83 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Wang et al [31] studied the evolution of the pore size distribution of MX80-sand bentonite hydrated under isochoric conditions; MIP tests, performed on samples equilibrated at different values of suction, showed that the most significant changes in PSD were taking place close to saturated conditions. Similar results were obtained by Niu et al [19] on GMZ bentonite. Seiphoori et al [25] analysed the evolution of the fabric of granular MX80 bentonite under isochoric conditions, relating it to changes in the water retention behaviour; they performed wetting-drying cycles that led to hysteretic response of the water retention curve; MIP results were obtained at several stages of the wetting-drying cycles showing that the hysteretic water retention behaviour could be related to the evolution of the PSD.…”

Section: Introductionsupporting

confidence: 91%

Volume change response and fabric evolution of granular MX80 bentonite along different hydro-mechanical stress paths

et al. 2022

View full text Add to dashboard Cite

Despite the increasing understanding of bentonite behaviour, there is still missing evidence on how different hydro-mechanical loadings, including sequences of hydration and compression, affect the fabric and the volume change behaviour of the material. It is generally assumed that the interplay between the behaviour of clay assemblages and the overall fabric of the material is the reason of having final states that are dependent on the stress path followed. Here the results of an experimental campaign aiming to study these factors are reported and discussed. Free swelling and swelling pressure tests were performed, both followed by compression to a relatively high stress. The experimental program involved various samples that were dismantled at intermediate states in order to perform microstructural observations by means of mercury intrusion porosimetry and electronic scanning microscopy. It was observed that while the void ratio at a given stress level depends on the stress path, subsequent compression led to a unique virgin compression line. The data obtained at the microscale gave further insight for an interpretation of the volume change behaviour observed at the macroscale, showing that at high stress the material tends to recover the same fabric regardless of the path to saturation.

show abstract

Section: Introductionsupporting

confidence: 91%

Volume change response and fabric evolution of granular MX80 bentonite along different hydro-mechanical stress paths

et al. 2022

View full text Add to dashboard Cite

show abstract

“…The residual fluid potential state

{\underline{R}}^{w}

is defined as

{\underline{R}}^{w} = \underline{Φ} - \tilde{\nabla Φ} ξ .

Note that

{\underline{R}}^{w}

is null for a uniform fluid pressure potential. Here, the soil–water retention curve 66‐68 is described by the celebrated van Genuchen equation 69 as

S_{r} = S_{1} + (S_{2} - S_{1}) {([], 1 + {(\frac{s}{s_{a}})}^{n})}^{(1 - n) / n},

where

s

is matric suction (e.g.,

s = - p_{w}

assuming passive air pressure), and

S_{1}

S_{2}

s_{a}

, and

n

are material constants. In this study, it is assumed that

S_{1} = 0

and

S_{2} = 1

.…”

Section: Unsaturated Fracture Periporomechanics For Unguided Crackingmentioning

confidence: 99%

“…Note that ℛ w is null for a uniform fluid pressure potential. Here, the soil-water retention curve [66][67][68] is described by the celebrated van Genuchen equation 69 as…”

Section: Unsaturated Periporomechanicsmentioning

confidence: 99%

Computational multiphase periporomechanics for unguided cracking in unsaturated porous media

Menon

Song

2022

Numerical Meth Engineering

Self Cite

View full text Add to dashboard Cite

In this article, we formulate and implement a computational multiphase periporomechanics paradigm for unguided fracturing in unsaturated porous media assuming passive pore air pressure. The same governing equation for the solid phase applies on and off cracks. Crack formation in this framework is autonomous, requiring no prior estimates of crack topology. As a new contribution, an energy-based criterion for arbitrary crack formation is formulated using the peridynamic effective force state for unsaturated porous media. Unsaturated fluid flow in the fracture space is modeled in a simplified way in line with the nonlocal formulation of unsaturated fluid flow in the bulk. The formulated unsaturated fracturing periporomechanics is numerically implemented through an implicit fractional step algorithm in time and a two-phase mixed meshless method in space. The two-stage operator split converts the coupled periporomechanics problem into an undrained deformation and fracture problem and an unsaturated fluid flow in the deformed skeleton configuration. Numerical simulations of in-plane open and shear cracking are conducted to validate the accuracy and robustness of the fracturing unsaturated periporomechanics model.Then numerical examples of wing cracking and nonplanar cracking in unsaturated soil specimens are presented to demonstrate the efficacy of the proposed multiphase periporomechanics paradigm for unguided cracking in unsaturated porous media.

show abstract

“…The advantage of applying an external force instead of actual pressure to drive the fluid flow is that the confined water can remain longitudinally homogeneous under a constant external field 32 . This is a crucial factor for the planar Poiseuille flow through a narrow pore 33 . This approach has been extensively used in other studies to simulate the transport behaviors of nanoconfined water flow 34–36 …”

Section: Introductionmentioning

confidence: 99%

Nonequilibrium molecular dynamics (NEMD) modeling of nanoscale hydrodynamics of clay‐water system at elevated temperature

Zhang

Song

2022

Num Anal Meth Geomechanics

Self Cite

View full text Add to dashboard Cite

The engineering problems involving clay under non‐isothermal conditions (e.g., geothermal energy harvest, landfill cover system, and nuclear waste disposal) are multiscale and multiphysics by nature. The nanoscale hydrodynamics of clay at elevated temperature is essential in developing a physics‐based multiscale model for clay under non‐isothermal conditions. The nonequilibrium molecular dynamics (NEMD) is a useful tool to study the nanoscale hydrodyndamics of clay. This article presents an NEMD modeling of hydrodynamics of clay nanopores at elevated temperatures. Water flow confined in pyrophyllite and montmorillonite clay nanopores is investigated. The nonequilibrium state is maintained by uniformly exerting an external force on each water molecule. The NEMD simulations have provided a molecular‐scale perspective of temperature effect on clay‐water density, water flow velocity, shear viscosity, clay‐water slip length, hydraulic conductivity, and clay‐water friction coefficient. The numerical results have shown a strong temperature dependence of fluid flow velocity, shear viscosity, clay‐water slip length, and hydraulic conductivity at the nanoscale. We have validated the applicability of cubic law in determining hydraulic conductivity at the nanopore scale at elevated temperatures. It is found from our numerical results that slip clay‐water boundary condition is an essential factor in properly determining nanoscale fluid flow velocity. By numerical examples, we also study the impact of nanopore size and clay layer thickness on the hydrodynamics of the clay‐water system.

show abstract

Unsaturated permeability of Gaomiaozi bentonite under partially free-swelling conditions

Cited by 33 publications

References 83 publications

Volume change response and fabric evolution of granular MX80 bentonite along different hydro-mechanical stress paths

Volume change response and fabric evolution of granular MX80 bentonite along different hydro-mechanical stress paths

Computational multiphase periporomechanics for unguided cracking in unsaturated porous media

Nonequilibrium molecular dynamics (NEMD) modeling of nanoscale hydrodynamics of clay‐water system at elevated temperature

Contact Info

Product

Resources

About