View in EDS

Evaluating the hydraulic and transport properties of peat soil using pore network modeling and X-ray micro computed tomography.

Saved in:
Bibliographic Details
Title: Evaluating the hydraulic and transport properties of peat soil using pore network modeling and X-ray micro computed tomography.
Authors: Gharedaghloo, Behrad1 bghareda@uwaterloo.ca, Price, Jonathan S.1 jsprice@uwaterloo.ca, Rezanezhad, Fereidoun2 frezanez@uwaterloo.ca, Quinton, William L.3 wquinton@wlu.ca
Source: Journal of Hydrology. Jun2018, Vol. 561, p494-508. 15p.
Subjects: Peat soils, Pollutants, Hydraulic conductivity, Computed tomography, Computational fluid dynamics
Abstract: Micro-scale properties of peat pore space and their influence on hydraulic and transport properties of peat soils have been given little attention so far. Characterizing the variation of these properties in a peat profile can increase our knowledge on the processes controlling contaminant transport through peatlands. As opposed to the common macro-scale (or bulk) representation of groundwater flow and transport processes, a pore network model (PNM) simulates flow and transport processes within individual pores. Here, a pore network modeling code capable of simulating advective and diffusive transport processes through a 3D unstructured pore network was developed; its predictive performance was evaluated by comparing its results to empirical values and to the results of computational fluid dynamics (CFD) simulations. This is the first time that peat pore networks have been extracted from X-ray micro-computed tomography (µCT) images of peat deposits and peat pore characteristics evaluated in a 3D approach. Water flow and solute transport were modeled in the unstructured pore networks mapped directly from µCT images. The modeling results were processed to determine the bulk properties of peat deposits. Results portray the commonly observed decrease in hydraulic conductivity with depth, which was attributed to the reduction of pore radius and increase in pore tortuosity. The increase in pore tortuosity with depth was associated with more decomposed peat soil and decreasing pore coordination number with depth, which extended the flow path of fluid particles. Results also revealed that hydraulic conductivity is isotropic locally, but becomes anisotropic after upscaling to core-scale; this suggests the anisotropy of peat hydraulic conductivity observed in core-scale and field-scale is due to the strong heterogeneity in the vertical dimension that is imposed by the layered structure of peat soils. Transport simulations revealed that for a given solute, the effective diffusion coefficient decreases with depth due to the corresponding increase of diffusional tortuosity. Longitudinal dispersivity of peat also was computed by analyzing advective-dominant transport simulations that showed peat dispersivity is similar to the empirical values reported in the same peat soil; it is not sensitive to soil depth and does not vary much along the soil profile. [ABSTRACT FROM AUTHOR]
Copyright of Journal of Hydrology is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database: Engineering Source
FullText Text:
  Availability: 0
Header DbId: egs
DbLabel: Engineering Source
An: 130223548
AccessLevel: 6
PubType: Academic Journal
PubTypeId: academicJournal
PreciseRelevancyScore: 0
IllustrationInfo
Items – Name: Title
  Label: Title
  Group: Ti
  Data: Evaluating the hydraulic and transport properties of peat soil using pore network modeling and X-ray micro computed tomography.
– Name: Author
  Label: Authors
  Group: Au
  Data: <searchLink fieldCode="AR" term="%22Gharedaghloo%2C+Behrad%22">Gharedaghloo, Behrad</searchLink><relatesTo>1</relatesTo><i> bghareda@uwaterloo.ca</i><br /><searchLink fieldCode="AR" term="%22Price%2C+Jonathan+S%2E%22">Price, Jonathan S.</searchLink><relatesTo>1</relatesTo><i> jsprice@uwaterloo.ca</i><br /><searchLink fieldCode="AR" term="%22Rezanezhad%2C+Fereidoun%22">Rezanezhad, Fereidoun</searchLink><relatesTo>2</relatesTo><i> frezanez@uwaterloo.ca</i><br /><searchLink fieldCode="AR" term="%22Quinton%2C+William+L%2E%22">Quinton, William L.</searchLink><relatesTo>3</relatesTo><i> wquinton@wlu.ca</i>
– Name: TitleSource
  Label: Source
  Group: Src
  Data: <searchLink fieldCode="JN" term="%22Journal+of+Hydrology%22">Journal of Hydrology</searchLink>. Jun2018, Vol. 561, p494-508. 15p.
– Name: Subject
  Label: Subjects
  Group: Su
  Data: <searchLink fieldCode="DE" term="%22Peat+soils%22">Peat soils</searchLink><br /><searchLink fieldCode="DE" term="%22Pollutants%22">Pollutants</searchLink><br /><searchLink fieldCode="DE" term="%22Hydraulic+conductivity%22">Hydraulic conductivity</searchLink><br /><searchLink fieldCode="DE" term="%22Computed+tomography%22">Computed tomography</searchLink><br /><searchLink fieldCode="DE" term="%22Computational+fluid+dynamics%22">Computational fluid dynamics</searchLink>
– Name: Abstract
  Label: Abstract
  Group: Ab
  Data: Micro-scale properties of peat pore space and their influence on hydraulic and transport properties of peat soils have been given little attention so far. Characterizing the variation of these properties in a peat profile can increase our knowledge on the processes controlling contaminant transport through peatlands. As opposed to the common macro-scale (or bulk) representation of groundwater flow and transport processes, a pore network model (PNM) simulates flow and transport processes within individual pores. Here, a pore network modeling code capable of simulating advective and diffusive transport processes through a 3D unstructured pore network was developed; its predictive performance was evaluated by comparing its results to empirical values and to the results of computational fluid dynamics (CFD) simulations. This is the first time that peat pore networks have been extracted from X-ray micro-computed tomography (µCT) images of peat deposits and peat pore characteristics evaluated in a 3D approach. Water flow and solute transport were modeled in the unstructured pore networks mapped directly from µCT images. The modeling results were processed to determine the bulk properties of peat deposits. Results portray the commonly observed decrease in hydraulic conductivity with depth, which was attributed to the reduction of pore radius and increase in pore tortuosity. The increase in pore tortuosity with depth was associated with more decomposed peat soil and decreasing pore coordination number with depth, which extended the flow path of fluid particles. Results also revealed that hydraulic conductivity is isotropic locally, but becomes anisotropic after upscaling to core-scale; this suggests the anisotropy of peat hydraulic conductivity observed in core-scale and field-scale is due to the strong heterogeneity in the vertical dimension that is imposed by the layered structure of peat soils. Transport simulations revealed that for a given solute, the effective diffusion coefficient decreases with depth due to the corresponding increase of diffusional tortuosity. Longitudinal dispersivity of peat also was computed by analyzing advective-dominant transport simulations that showed peat dispersivity is similar to the empirical values reported in the same peat soil; it is not sensitive to soil depth and does not vary much along the soil profile. [ABSTRACT FROM AUTHOR]
– Name: AbstractSuppliedCopyright
  Label:
  Group: Ab
  Data: <i>Copyright of Journal of Hydrology is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.)
PLink https://search.ebscohost.com/login.aspx?direct=true&site=eds-live&db=egs&AN=130223548
RecordInfo BibRecord:
  BibEntity:
    Identifiers:
      – Type: doi
        Value: 10.1016/j.jhydrol.2018.04.007
    Languages:
      – Code: eng
        Text: English
    PhysicalDescription:
      Pagination:
        PageCount: 15
        StartPage: 494
    Subjects:
      – SubjectFull: Peat soils
        Type: general
      – SubjectFull: Pollutants
        Type: general
      – SubjectFull: Hydraulic conductivity
        Type: general
      – SubjectFull: Computed tomography
        Type: general
      – SubjectFull: Computational fluid dynamics
        Type: general
    Titles:
      – TitleFull: Evaluating the hydraulic and transport properties of peat soil using pore network modeling and X-ray micro computed tomography.
        Type: main
  BibRelationships:
    HasContributorRelationships:
      – PersonEntity:
          Name:
            NameFull: Gharedaghloo, Behrad
      – PersonEntity:
          Name:
            NameFull: Price, Jonathan S.
      – PersonEntity:
          Name:
            NameFull: Rezanezhad, Fereidoun
      – PersonEntity:
          Name:
            NameFull: Quinton, William L.
    IsPartOfRelationships:
      – BibEntity:
          Dates:
            – D: 01
              M: 06
              Text: Jun2018
              Type: published
              Y: 2018
          Identifiers:
            – Type: issn-print
              Value: 00221694
          Numbering:
            – Type: volume
              Value: 561
          Titles:
            – TitleFull: Journal of Hydrology
              Type: main
ResultId 1