Procedure to detect the contact of platy cohesive particles in discrete element analysis

Bayesteh, Hamed; Mirghasemi, Ali Asghar

doi:10.1016/j.powtec.2013.04.001

Cited by 14 publications

(7 citation statements)

References 38 publications

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“…Nanoscale simulations of clay aggregation at the scale of individual layers have the potential to support the development of dual structure models by providing insight into the microstructure of clayey media (Figure ). Efforts in this direction have modeled either pairs of clay particles in liquid water [using molecular dynamics (MD) or Monte Carlo (MC) simulations with an all-atom , or implicit solvent] , or assemblages of hundreds of clay particles (using coarse-grained simulations with interparticle interaction potentials derived from all-atoms MD simulations or DLVO theory). ,− Most studies to date, with a few exceptions, ,, have focused on the swelling mechanics of Na-smectite in pure liquid water.…”

Section: The Nanoscale View: Chemical Controls On the Mechanics Of Cl...mentioning

confidence: 99%

“…A key challenge associated with the coarse-grained models outlined above is the difficulty of developing interparticle interaction models that accurately reflect both long- and short-range interactions. Most of the models developed to date assume that particle–particle interactions are repulsive at all distances, and none of them predicts the coexistence of osmotic and crystalline hydrates. − Several coarse-grained models have reported reasonable agreement with experimental data on the swelling pressure of Na-smectite in pure water, , but none has yet been validated against data on the detailed pore-size distribution of compacted smectite , or against properties that are particularly sensitive to pore-size distribution, such as anion exclusion or permeability.…”

Section: The Nanoscale View: Chemical Controls On the Mechanics Of Cl...mentioning

confidence: 99%

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Clay, Water, and Salt: Controls on the Permeability of Fine-Grained Sedimentary Rocks

Bourg

Ajo‐Franklin

2017

Acc. Chem. Res.

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The ability to predict the permeability of fine-grained soils, sediments, and sedimentary rocks is a fundamental challenge in the geosciences with potentially transformative implications in subsurface hydrology. In particular, fine-grained sedimentary rocks (shale, mudstone) constitute about two-thirds of the sedimentary rock mass and play important roles in three energy technologies: petroleum geology, geologic carbon sequestration, and radioactive waste management. The problem is a challenging one that requires understanding the properties of complex natural porous media on several length scales. One inherent length scale, referred to hereafter as the mesoscale, is associated with the assemblages of large grains of quartz, feldspar, and carbonates over distances of tens of micrometers. Its importance is highlighted by the existence of a threshold in the core scale mechanical properties and regional scale energy uses of shale formations at a clay content X ≈ 1/3, as predicted by an ideal packing model where a fine-grained clay matrix fills the gaps between the larger grains. A second important length scale, referred to hereafter as the nanoscale, is associated with the aggregation and swelling of clay particles (in particular, smectite clay minerals) over distances of tens of nanometers. Mesoscale phenomena that influence permeability are primarily mechanical and include, for example, the ability of contacts between large grains to prevent the compaction of the clay matrix. Nanoscale phenomena that influence permeability tend to be chemomechanical in nature, because they involve strong impacts of aqueous chemistry on clay swelling. The second length scale remains much less well characterized than the first, because of the inherent challenges associated with the study of strongly coupled nanoscale phenomena. Advanced models of the nanoscale properties of fine-grained media rely predominantly on the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, a mean field theory of colloidal interactions that accurately predicts clay swelling in a narrow range of conditions (low salinity, low compaction, Na counterion). An important feature of clay swelling that is not predicted by these models is the coexistence, in most conditions of aqueous chemistry and dry bulk density, of two types of pores between parallel smectite particles: mesopores with a pore width of >3 nm that are controlled by long-range interactions (the osmotic swelling regime) and nanopores with a pore width <1 nm that are controlled by short-range interactions (the crystalline swelling regime). Nanogeochemical characterization and simulation techniques, including coarse-grained and all-atom molecular dynamics simulations, hold significant promise for the development of advanced constitutive relations that predict this coexistence and its dependence on aqueous chemistry.

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Section: The Nanoscale View: Chemical Controls On the Mechanics Of Cl...mentioning

confidence: 99%

Section: The Nanoscale View: Chemical Controls On the Mechanics Of Cl...mentioning

confidence: 99%

Clay, Water, and Salt: Controls on the Permeability of Fine-Grained Sedimentary Rocks

Bourg

Ajo‐Franklin

2017

Acc. Chem. Res.

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“…For this purpose, a computer code was developed to find particles in repulsive, attractive and mechanical contact forces [16,17]. Based on the common DEM validation methods, verifications were performed for the present model and are presented elsewhere [16].…”

Section: Discussionmentioning

confidence: 99%

“…The diffused double layer (DDL) repulsion and Van der Waals attraction are the main forces between clay minerals based on their SSA, CEC and pore fluid chemistry [22]. The authors have recently developed a new method to use a DEM algorithm to model clay behavior considering inter-particle forces [17]. The coefficient of permeability is calculated by fitting the Terzaghi theory of consolidation [23] to the observed numerical one-dimensional consolidation time-settlement observation.…”

Section: Simulation Methodsmentioning

confidence: 99%

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Numerical Simulation of Tortuosity Effect on the Montmorillonite Permeability

Mirghasemi

Bayesteh

2015

Procedia Engineering

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This study analyzed the association between the coefficient of permeability of clayey sealing materials and their tortuosity. Montmorillonite was selected because it is used as a barrier in geo-environmental projects and its sensitive structure results in wide variations in permeability when in contact with pore fluids. A DEM code was developed by considering mechanical force, diffuse double layer repulsion, and Van der Waals attraction as the inter-particle interaction. The coefficient of permeability was calculated by simulating a consolidation test and the DEM simulations were compared with experimental data. The results showed that the coefficient of permeability decreased as the void ratio decreased. At the same void ratio, there was a deviation between the coefficient of permeability for clay-electrolyte systems caused by the micro-fabric and variations in tortuosity. Micro-fabric evolution during loading showed that increasing the stress state caused reorientation of the particles perpendicular to the direction of loading and increased anisotropy of the particle orientation, increasing the tortuous flow path.

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Effect of initial packing density, stress level and particle size ratio on the behavior of binary granular material: a micromechanical approach

2020

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Procedure to detect the contact of platy cohesive particles in discrete element analysis

Cited by 14 publications

References 38 publications

Clay, Water, and Salt: Controls on the Permeability of Fine-Grained Sedimentary Rocks

Clay, Water, and Salt: Controls on the Permeability of Fine-Grained Sedimentary Rocks

Numerical Simulation of Tortuosity Effect on the Montmorillonite Permeability

Effect of initial packing density, stress level and particle size ratio on the behavior of binary granular material: a micromechanical approach

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