Seepage and consolidation of bentonite saturated with pure- or salt-water by the method of unified molecular dynamics and homogenization analysis

Ichikawa, Yasuaki; Kawamura, Katsuyuki; Nakano, Miki; Kitayama, Kazumi; Seiki, Takafumi; Nattavut, Theramast

doi:10.1016/s0013-7952(00)00095-8

Cited by 27 publications

(22 citation statements)

References 12 publications

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“…Moreover, the pore space comprised only intergranular porosity with no nanoporosity such as encountered in clays. Ichikawa et al (1999Ichikawa et al ( , 2001Ichikawa et al ( , 2004a and Wang et al (2003) employed the Homogenization of Periodic Media to model fluid flow through clays. The microscopic and the macroscopic fluid flow equations were obtained from the Navier-Stokes equations using double scale asymptotic expansions, the two levels of description being related by the macroscopic permeability.…”

Section: Multiscale Modelling Of Fluid Flow In Geomaterialsmentioning

confidence: 99%

“…With respect to existing works on compacted bentonites (Bouchelaghem and Jozja, 2009a,b;Ichikawa et al, 1999Ichikawa et al, , 2001Ichikawa et al, , 2004aWang et al, 2003) which are all based on simplified microstructures (Poiseuille-like flow for lamellae of hydrated montmorillonite, symmetrical arrangements of spherical or cylindrical grains on the mesoscopic scale), the macroscopic permeability tensor is computed on real microstructures, while both mesopores and non-smectite grains are taken into account, leading to new effective permeability formulations. According to Baltean (1999) and Wodie (1992), the effective permeability will be obtained on the macroscopic scale by upscaling from the mesoscopic scale alone, consisting here of the arrangement of clay aggregates, inter-aggregate voids and non-smectite grains.…”

Section: Modelling Approach and Outline Of The Papermentioning

confidence: 99%

“…The derivation of the effective fluid flow behaviour through periodic media has been detailed in previous works for the case of constant fluid viscosity (Baltean et al, 2003;Baltean, 1999;Ichikawa et al, 1999Ichikawa et al, , 2001Levy, 1987;Wodie, 1992). For random media, the homogenization procedure is similar to the homogenization of periodic media, provided that the assumption of periodicity is replaced by the assumption of local statistical homogeneity and ergodicity (Rubinstein and Torquato, 1989;Torquato, 2005).…”

Section: Mesoscopic Description Of the Domain Occupied By Clay Aggregmentioning

confidence: 99%

“…Fluid viscosity µ = µ(y ′ ) is taken to vary locally in the microstructure, in order to account for the "ice sheet" effect of viscosity increase near the particle surface (Ichikawa et al, 1999(Ichikawa et al, , 2001(Ichikawa et al, , 2004aPusch and Yong, 2006). The mesoscopic description of flow in clay particles is obtained by performing an asymptotic analysis in terms of the parameter ε ′ (Bensoussan et al, 1978;Levy, 1987;Sanchez-Palencia, 1980;Rubinstein and Torquato, 1989), leading to (Bouchelaghem and Jozja, 2009a):…”

Section: Mesoscopic Description Of the Domain Occupied By Clay Aggregmentioning

confidence: 99%

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Fluid flow and effective conductivity calculations on numerical images of bentonite microstructure

Bouchelaghem

Pusch

2017

Applied Clay Science

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Hydraulic conductivities of compacted water-saturated bentonite were computed based on the real microstructure. The Homogenization of Periodic Media approach employed fully acknowledges the heterogeneous and multiscale microstructure of clay, as well as locally varying physical flow properties. Consequently, three levels of description were considered : the microscopic level of clay particles, the mesoscopic level of clay aggregates, mineral grains and inter-aggregate porosity, and the macroscopic level of the sample subjected to fluid pressure gradients in the laboratory. Starting from the local description of fluid flow, the expression of the effective hydraulic conductivity tensor was derived. The soft and dense gels and the open voids may form a connected flow path or remain occluded. The local problems were solved on the microstructure obtained from a digitalized micrograph by image analysis. The contribution to macroscopic flow by the soft and dense gels was investigated in various configurations, and comparisons were made with hydraulic conductivity data for MX-80 bentonite.

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Section: Multiscale Modelling Of Fluid Flow In Geomaterialsmentioning

confidence: 99%

Section: Modelling Approach and Outline Of The Papermentioning

confidence: 99%

Section: Mesoscopic Description Of the Domain Occupied By Clay Aggregmentioning

confidence: 99%

Section: Mesoscopic Description Of the Domain Occupied By Clay Aggregmentioning

confidence: 99%

See 2 more Smart Citations

Fluid flow and effective conductivity calculations on numerical images of bentonite microstructure

Bouchelaghem

Pusch

2017

Applied Clay Science

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“…For instance, the lateral self-diffusivity of water to a crystal surface is different from a bulk surface in the case of a water-brucite surface (Sakuma et al 2003), a water-muscovite mica surface (Sakuma and Kawamura 2009), and others. The dynamic property anomalies on solid-liquid interfaces affect the properties of bulk rock, e.g., permeability (Ichikawa et al 2001).…”

Section: Introductionmentioning

confidence: 99%

Structure and properties of forsterite-MgSiO3 liquid interface: molecular dynamics study

Noritake

Kawamura

2014

Prog Earth Planet Sci

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The mechanical properties of partially molten rock, such as their permeabilities and viscosities, are important properties in geological processes. We performed molecular dynamics simulations in terms of structures and diffusivities in forsterite-MgSiO 3 liquid interfaces to obtain the nanoscale dynamic properties and structure of the interface. The characteristic structure of the forsterite-MgSiO 3 liquid interfaces was observed in the simulations. In the layered structure of the altered surfaces, Si-rich and Mg-rich layers exist alternately in the vicinity of the crystal-liquid interfaces. The layered structure might be formed by the strength difference between Si-O covalent bonds and Mg-O ionic bonds. The difference in the layered structure, indicated by the thickness of the MgSiO 3 liquid film, might be caused by the difference in degrees of freedom of the configuration in the liquid film. The two-dimensional diffusivity of oxygen atoms parallel to the interface is controlled by two factors. One factor is the thickness of the liquid film, which decreases oxygen diffusivity with decreasing film thickness. The other is the composition of the sliced layer, where oxygen diffusivity increases with increasing Mg/Si ratio. The effect of the crystal-liquid interface found in this study is negligible in texturally equilibrated rocks. However, the interface can affect the melt flow in deformed samples because a grain boundary melt film with a thickness of several nanometers exists stably in deformed partially molten rock.

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Secondary consolidation of clay as an anomalous diffusion process

Cosenza

Korošak

2014

Num Anal Meth Geomechanics

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International audienceSecondary consolidation of clay soil is considered as a result of anomalous diffusion of pore water pressure from the micropores to the macropores. By using simplified pore geometry, a heuristic approach allows us to infer the expression of the associated rate of vertical secondary deformation written as a fractional derivative of the pore pressure. The insertion of this expression into the 1D Terzaghi's theory leads to a particular type of time-fractional diffusion equation of the pore pressure that is solved semi-analytically. The advantage of such theoretical approach stems from the concise and compact way of treating the secondary consolidation. Only two additional parameters are needed: the fractional order, nu, and the fractional viscosity factor theta, both accounting for the physicochemical interactions between pore fluid and clay particles. This theoretical approach is tested on experimental data obtained from the Cubzac-les-Ponts clay soil intensively studied for secondary consolidation. This application shows a good agreement between the data and the predicted values confirming the interest of the initial assumption and the use of the fractional derivatives formalism. Moreover, good correlations between the inverted fractional parameters and the empirical secondary consolidation index C-alpha measured independently are obtained: the fractional order nu, if experimentally calibrated, can be used as a reasonable estimator of the slope of the secondary consolidation portion of consolidation curve

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Seepage and consolidation of bentonite saturated with pure- or salt-water by the method of unified molecular dynamics and homogenization analysis

Cited by 27 publications

References 12 publications

Fluid flow and effective conductivity calculations on numerical images of bentonite microstructure

Fluid flow and effective conductivity calculations on numerical images of bentonite microstructure

Structure and properties of forsterite-MgSiO3 liquid interface: molecular dynamics study

Secondary consolidation of clay as an anomalous diffusion process

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