Composite ellipsoidal particles to simulate charge anisotropy in particle-scale simulations of kaolinite
File(s)
Accepted version
Author(s)
Bandera, Sara
O'Sullivan, Catherine
Tangney, Paul
Angioletti-Uberti, stefano
Type
Journal Article
Abstract
This paper outlines a new approach to use coarse-grained molecular dynamics (CGMD) and the Gay–Berne (GB) potential to simulate the compression of kaolinite saturated with water at an acidic pH ( = 4) in a low (1 mM) ion concentration solution. To overcome the limitations of the standard GB potential and capture the charge heterogeneity on the surface of kaolinite particles under acidic pH conditions, each clay platelet is modelled using a two-ellipsoid composite particle. The molecular dynamics software Large-scale Atomic/Molecular Massively Parallel Software was employed to generate virtual monodisperse samples containing 1000 composite particles and to simulate isotropic compression at 100 kPa. The observed macro-scale response in void ratio–effective stress space lay above the response obtained in a simulation that used an equivalent CGMD model developed to simulate alkaline (pH = 8) pore water conditions. This is in qualitative agreement with available experimental data for one-dimensional compression. A post-compression qualitative observation of two virtual samples revealed a book-house-type fabric in the sample with acidic pore fluid, whereas a turbostatic-type fabric was observed when an alkaline pore fluid was simulated. These observations are also in qualitative agreement with scanning electron microscopy data reported in the literature.
Date Issued
2024-03-01
Date Acceptance
2024-04-18
Citation
Geotechnique Letters, 2024, 14 (1), pp.1-8
ISSN
2045-2543
Publisher
ICE Publishing
Start Page
1
End Page
8
Journal / Book Title
Geotechnique Letters
Volume
14
Issue
1
Copyright Statement
© 2024 Emerald Publishing Ltd. This is the author’s accepted manuscript made available under a CC-BY licence in accordance with Imperial’s Research Publications Open Access policy (www.imperial.ac.uk/oa-policy)
License URL
Publication Status
Published
Date Publish Online
2024-05-29