Observatorio de I+D+i UPM

Memorias de investigación
Communications at congresses:
Percolation in soils at Different Bulk Densities: Porosity, Connectivity and Grey Threshold
Year:2011
Research Areas
  • Physics chemical and mathematical,
  • Engineering
Information
Abstract
To improve percolation modelling on soils the geometrical properties of the pore space must be understood; this includes porosity, particle and pore size distribution and connectivity of the pores. A study was conducted with a soil at different bulk densities based on 3D grey images acquired by X-ray computed tomography. The objective was to analyze the effect in percolation of aspects of pore network geometry and discuss the influence of the grey threshold applied to the images. A model based on random walk algorithms was applied to the images, combining five bulk densities with up to six threshold values per density. This allowed for a dynamical perspective of soil structure in relation to water transport through the inclusion of percolation speed in the analyses. To evaluate separately connectivity and isolate the effect of the grey threshold, a critical value of 35% of porosity was selected for every density. This value was the smallest at which total-percolation walks appeared for the all images of the same porosity and may represent a situation of percolation comparable among bulks densities. This criterion avoided an arbitrary decision in grey thresholds. Besides, a random matrix simulation at 35% of porosity with real images was used to test the existence of pore connectivity as a consequence of a non-random soil structure. The results showed that porosity distribution with depth had the greatest oscillations for the smallest density, while random matrix presented a scattered distribution around the 35% mean due to the lack of structure. Random matrix presented a normal distribution of percolation speed. In general, percolation speed for real images diminished with bulk density for total percolation walks. The simulated percolation speed for these images were not distributed according to a Gaussian curve, so it was not possible to assume the Darcy's Law to explain percolation in these soils.
International
Si
Congress
AGU Fall Meeting 2011
960
Place
San Francisco, USA
Reviewers
Si
ISBN/ISSN
0096-3941
Start Date
05/12/2011
End Date
09/12/2011
From page
1303
To page
1303
AGU Fall Meeting Abstracts Vol.H
Participants
  • Autor: Margarita Ruiz Ramos (UPM)
  • Autor: Daniel del Valle (UCLM)
  • Autor: P. Baveye (University of Abertay, Dundee)
  • Autor: Ana Maria Tarquis Alfonso (UPM)
Research Group, Departaments and Institutes related
  • Creador: Grupo de Investigación: Grupo de Automatización en Señal y Comunicaciones (GASC)
  • Centro o Instituto I+D+i: Centro de Estudios e Investigación para la Gestión de Riesgos Agrarios Medioambientales (CEIGRAM)
  • Grupo de Investigación: Grupo de Sistemas Agrarios (AgSystems)
  • Departamento: Producción Vegetal: Fitotecnia
  • Departamento: Matemática Aplicada a la Ingeniería Agronómica
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