Multi-dimensional chemo-osmotic consolidation of clays

Li, Y.; Cleall, Peter John; Thomas, Hywel Rhys

doi:10.1016/j.compgeo.2011.02.005

Cited by 9 publications

(4 citation statements)

References 28 publications

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“…Xue et al [8,9] proposed a gashydraulic-solid coupling model that can describe the dynamic behavior of settlement and LFG flow in landfill, where after, four models were established of biological-thermo-hydro coupling model of landfill gas migration, hydro-biological-chemical coupling model of leachate migration and transformation in landfill under the effect of aerobe and anaerobe degradation, hydro-chemical coupling model of pollutant migration in composite liner system and thermo-hydro-mechanical coupling model on dry cracking of closure cover system of landfill under the effect of heat quantity changing and vapor migration. Li [10] presented a twodimensional model of chemo-osmotic consolidation of clays in multi-dimensional domains, with volumetric strains induced by both changes in the chemistry and osmotically driven pore water flow considered. It was found that the consolidation process was dominated by osmotic consolidation in the early stages and subsequently by chemical consolidation.…”

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A Three-Dimensional Model Coupled Mechanical Consolidation and Contaminant Transport

Zhang¹,

Fang²

2016

JRST

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Contaminant transport is a common process for a waste disposal site, which is a practical concern in geo-environmental field. It is essential to study the contaminant transport behavior in impermeable clay liner. Considering the anisotropy of a clay barrier in permeability, a three-dimensional model coupled mechanical consolidation and contaminant transport is developed for simulation of contaminant transport through a deforming porous medium. This is based on the combination of Biot's theory and the theory of contaminant transport. Meanwhile, porosity is viewed as a coupling parameter. The influence of soil consolidation deformation and permeability anisotropy on contaminant transport can thus be determined reasonably. Transport equations are solved by using the finite-element software COMSOL Multiphysics. A parametric study has moreover been conducted to understand the influence of contaminant source types and adsorption modes, including constant contaminated source, attenuation contaminated source, linear adsorption, Freundlich adsorption, Langmuir adsorption. The simulation results indicate that the permeability anisotropy has a negligible effect on contaminant transport, adsorption modes have a significant impact on transport depth and range, and the concentration distribution of contaminant with different contaminated source types have showed a marked difference.

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confidence: 99%

A Three-Dimensional Model Coupled Mechanical Consolidation and Contaminant Transport

Zhang¹,

Fang²

2016

JRST

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“…Accurate assessment of clay liner performance is crucial to design landfill barriers for optimum containment of chemical solutes (Chen 2014). Variation of spatial dimension can influence the migration law of solutes (Li et al 2011). Therefore, it is essential to establish a three-dimensional model to investigate solute transport processes under complex engineering and geoenvironmental conditions.…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional fully coupled hydro-mechanical-chemical model for solute transport under mechanical and osmotic loading conditions

Masum

Tian

Sultana

2022

Environ Sci Pollut Res

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Mechanical deformation and chemico-osmotic consolidation of clay liners can change its intrinsic transport properties in all direction and can alter fluid and solute transport processes in the entire model domain. These phenomena are described inadequately by lower-dimensional models. Based on the Biot’s consolidation theory, fluid and solute mass conservation equations, a three-dimensional (3D) fully-coupled hydro-mechanical-chemical (HMC) model has been proposed in this study. The impacts of mechanical consolidation and chemico-osmotic consolidation on permeability, hydrodynamic dispersion, solute sorption, membrane efficiency, and chemical osmosis are considered in the model. The model is applied to evaluate performances of a single compacted clay liner (CCL) and a damaged geomembrane-compacted clay composite liner (GMB/CCL) to contain a generic landfill contaminant. Effect of model dimensionality on solute spread for CCL is found to be marginal, but for GMB/CCL the effect is significantly large. After 50-year simulation period, solute concentration at the half-length of the GMB/CCL liner is predicted to be 40% of the source concentration during 1D simulation, which is only 6% during the 3D simulation. The results revealed approximately 74% over-estimation of liner settlement in 1D simulation than that of the 3D for GMB/CL system. Solute spread accelerates (over-estimates) vertically than horizontally since overburden load and consequent mechanical loading-induced solute convection occurs in the same direction. However, in homogeneous and isotropic soils, horizontal spread retards the overall migration of contaminants, and it highlights the importance of 3D models to study solute transports under mechanical and chemico-osmotic loading conditions in semi-permeable clays, especially, for damaged geomembrane-clay liners. The results show the utility of geomembranes to reduce soil settlement, undulation, and restriction of solute migration. Furthermore, application of geomembrane can inhibit development of elevated negative excess pore water pressure at deeper portion of a clay liner.

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“…For instance bentonitic based compacted expansive clays play a critical role in the safety assessments of their capacity to act as a host rock of high-level long lived radioactive waste disposal sites. In addition, they act as a geochemical filter for environmental protection to inhibit the migration of contaminants from hazardous wastes in sanitary landfills [5].…”

Section: Introductionmentioning

confidence: 99%

A Two-Scale Computational Model of pH-Sensitive Expansive Porous Media

Ponce

Murad

Lima

2013

Journal of Applied Mechanics

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We propose a new two-scale model to compute the swelling pressure in colloidal systems with microstructure sensitive to changes from an outer bulk fluid in thermodynamic equilibrium with the electrolyte solution in the nanopores. The model is based on establishing the microscopic pore scale governing equations for a biphasic porous medium composed of surface charged macromolecules saturated by the aqueous electrolyte solution containing four monovalent ions [Formula: see text]. Ion exchange reactions occur at the surface of the particles leading to a-dependent surface charge density, giving rise to a nonlinear Neumann condition for the Poisson-Boltzmann problem for the electric double layer potential. The homogenization procedure, based on formal matched asymptotic expansions, is applied to up-scale the pore-scale model to the macroscale. Modified forms of Terzaghi's effective stress principle and mass balance of the solid phase, including a disjoining stress tensor and electrochemical compressibility, are rigorously derived from the upscaling procedure. New constitutive laws are constructed for these quantities incorporating the -dependency. The two-scale model is discretized by the finite element method and applied to numerically simulate a free swelling experiment induced by chemical stimulation of the external bulk solution.

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Multi-dimensional chemo-osmotic consolidation of clays

Cited by 9 publications

References 28 publications

A Three-Dimensional Model Coupled Mechanical Consolidation and Contaminant Transport

A Three-Dimensional Model Coupled Mechanical Consolidation and Contaminant Transport

Three-dimensional fully coupled hydro-mechanical-chemical model for solute transport under mechanical and osmotic loading conditions

A Two-Scale Computational Model of pH-Sensitive Expansive Porous Media

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