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| Titel |
Percolation properties of 3-D multiscale pore networks: how connectivity controls soil filtration processes |
| VerfasserIn |
E. M. A. Perrier, N. R. A. Bird, T. B. Rieutord |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 7, no. 10 ; Nr. 7, no. 10 (2010-10-18), S.3177-3186 |
| Datensatznummer |
250005017
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| Publikation (Nr.) |
 copernicus.org/bg-7-3177-2010.pdf |
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| Zusammenfassung |
| Quantifying the connectivity of pore networks is a key issue not only for
modelling fluid flow and solute transport in porous media but also for
assessing the ability of soil ecosystems to filter bacteria, viruses and any
type of living microorganisms as well inert particles which pose a
contamination risk. Straining is the main mechanical component of filtration
processes: it is due to size effects, when a given soil retains a conveyed
entity larger than the pores through which it is attempting to pass. We
postulate that the range of sizes of entities which can be trapped inside
soils has to be associated with the large range of scales involved in natural
soil structures and that information on the pore size distribution has to be
complemented by information on a critical filtration size (CFS) delimiting
the transition between percolating and non percolating regimes in multiscale
pore networks. We show that the mass fractal dimensions which are classically
used in soil science to quantify scaling laws in observed pore size
distributions can also be used to build 3-D multiscale models of pore networks
exhibiting such a critical transition. We extend to the 3-D case a new
theoretical approach recently developed to address the connectivity of 2-D
fractal networks (Bird and Perrier, 2009). Theoretical arguments based on
renormalisation functions provide insight into multi-scale connectivity and a
first estimation of CFS. Numerical experiments on 3-D prefractal media confirm
the qualitative theory. These results open the way towards a new methodology
to estimate soil filtration efficiency from the construction of soil
structural models to be calibrated on available multiscale data. |
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