MORPHOLOGY AND PEDOLOGIC CLASSIFICATION OF SWELLING SOILS

Swelling soils occur in nature in a predictable manner. The pedologist identifies, classifies, and characterizes these unique soils and delineates their occurrence on the landscape. The concept of Vertisols, for example, is that of a soil that is unstable because of a high content of expanding lattice clay. The morphology is marked by intersecting slickensides, parallelepiped structural aggregates, and horizons that are thin and poorly expressed near microhighs but that are thick and well expressed in microlows only a few feet (meters) away. Where not destroyed by man, these soils have gilgai relief. Soils having swelling potential but lacking the other features of Vertisols are classified in vertic subgrougs of other soil orders. By definition, these soils have more than 35 percent clay within a designated control section and a coefficient of linear extensibility of 0.09 or more or a potential linear extensibility of 2.4 in. (6 cm) or more. Vertisols and soils in vertic subgroups of other orders have the common property of instability because of swelling. They have a high plasticity index and a high liquid limit. They are characterized by a high content of expanding lattice clays, particularly montmorillonite. The micromorphology of swelling soils reveals a fabric of oriented clay particles along short-range shear planes.

• Record URL:
  • http://onlinepubs.trb.org/Onlinepubs/trr/1976/568/568-001.pdf
• Summary URL:
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• Supplemental Notes:
  • Publication of this paper sponsored by Committee on Environmental Factors Except Frost. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved.
• Authors:
  • Bartelli, Lindo J
  • McCormack, Donald E
• Conference:
  • 54th Annual Meeting of the Transportation Research Board
  • Location: Washington District of Columbia
  • Date: 1975-1-13 to 1975-1-17
• Publication Date: 1976

Media Info

• Media Type: Print
• Features: Figures; References; Tables;
• Pagination: pp 1-8
• Monograph Title: Swelling Soils
• Serial:
  • Transportation Research Record
  • Issue Number: 568
  • Publisher: Transportation Research Board
  • ISSN: 0361-1981

Subject/Index Terms

• TRT Terms: Classification; Clay; Expansive clays; Instability; Liquid limits; Montmorillonite; Morphology; Plasticity index; Soil mechanics; Soil stabilization; Soils; Swelling soils
• Old TRIS Terms: Pedological classification systems
• Subject Areas: Geotechnology; Highways;

Filing Info

• Accession Number: 00138135
• Record Type: Publication
• ISBN: 0309024811
• Files: TRIS, TRB
• Created Date: Sep 4 1976 12:00AM