EFFECTS OF DESICCATION ON THE HYDRAULIC CONDUCTIVITY VERSUS VOID RATIO RELATIONSHIP FOR A NATURAL CLAY

Undisturbed and reconstituted specimens of a soft gray Pleistocene clay were subjected to various degrees of desiccation, resaturated, and then tested to determine their hydraulic conductivity (k) versus void ratio (e) relationships. The log k versus e relationships for all of the specimens have a common shape that is characterized by a steep slope at high void ratios and a much flatter slope at lower void ratios. Desiccation affected primarily the magnitude, and not the shape, of the log k versus e relationships. With increasing degrees of desiccation, the relationships were displaced in the direction of increasing hydraulic conductivity. The desiccation-induced changes for the undisturbed specimens were greater than those exhibited by the reconstituted specimens. These characteristics of the log k versus e relationships can be explained in terms of the cluster model of clay fabric. At high void ratios, the steep slope of the log k versus e relationship is dominated by reductions in the sizes of the macropores surrounding the clusters. At lower void ratios, the increasing relative importance of pore-size reductions within the clusters is reflected in the decreasing slope of the log k versus e relationship. The generally higher hydraulic conductivity values with increasing degrees of desiccation in both the undisturbed and reconstituted samples reflect desiccation-induced shrinkage of clusters.

• Record URL:
  http://onlinepubs.trb.org/Onlinepubs/trr/1992/1369/1369-017.pdf
• Record URL:
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• Supplemental Notes:
  • This paper appears in Transportation Research Record No. 1369, Advances in Geotechnical Engineering. 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:
  • Shear, Dixie L
  • Olsen, Harold W
  • Nelson, Karl R
• Publication Date: 1992

Language

• English

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 130-135
• Monograph Title: Advances in geotechnical engineering
• Serial:
  • Transportation Research Record
  • Issue Number: 1369
  • Publisher: Transportation Research Board
  • ISSN: 0361-1981

Subject/Index Terms

• TRT Terms: Desiccation; Permeability coefficient; Shrinkage; Soft clays; Undisturbed samples; Void ratios
• Old TRIS Terms: Clusters (Clay fabric); Macropores; Reconstituted specimens
• Subject Areas: Geotechnology; Highways; Hydraulics and Hydrology; I42: Soil Mechanics;

Filing Info

• Accession Number: 00627126
• Record Type: Publication
• ISBN: 0309054109
• Files: TRIS, TRB
• Created Date: Mar 18 1993 12:00AM