INFLUENCE OF PROCEDURAL VARIABLES ON THE GRADIENT RATIO TEST

The gradient ratio (GR) test is a performance test used to determine the soil-geotextile system permeability and clogging behavior. Despite being a standard, the test has received much criticism, especially because of its poor reproducibility and its perceived inability to accurately model field behavior. Ideally, filtration behavior of soil-geotextile systems should depend only on the soil and geotextile properties. In practice, however, problems with the reproducibility of test results are related to the test's sensitivity to slight variations in test details and procedures. In addition, some optional procedures can have a significant effect on test results, while other required procedures appear to have little influence. A systematic study was performed to evaluate the effects of these procedures on GR test results. It was found that microfiltration of the in-flow water had a significant effect on filtration behavior. Chlorine algicide was effective in enhancing long-term filtration behavior, as was purging with carbon dioxide and slow saturation of the system. Placement of the soil specimen also influenced GR values; they were found to be lower for compacted specimens than for loosely placed specimens. Presoaking geotextiles had no observable effect on filtration behavior, and disturbance of the GR device during the early stages of the test caused immediate and significant changes in permeability and GR.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/01496115
• Corporate Authors:

  American Society for Testing and Materials (ASTM)

  100 Barr Harbor Drive, P.O. Box C700
  West Conshohocken, PA  United States  19428-2957
• Authors:
  • Fischer, G R
  • Mare, A D
  • Holtz, R D
• Publication Date: 1999-3

Language

• English

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 22-31
• Serial:
  • Geotechnical Testing Journal
  • Volume: 22
  • Issue Number: 1
  • Publisher: ASTM International
  • ISSN: 0149-6115
  • EISSN: 1945-7545
  • Serial URL: https://www.astm.org/products-services/standards-and-publications/geotechnical-testing-journal.html

Subject/Index Terms

• TRT Terms: Compacted soils; Filtration; Geotextiles; Loose soils; Percent saturation; Permeability; Soils; Test procedures; Variables
• Uncontrolled Terms: Gradient ratio tests
• Subject Areas: Geotechnology; Highways; I42: Soil Mechanics;

Filing Info

• Accession Number: 00809348
• Record Type: Publication
• Files: TRIS
• Created Date: Apr 18 2001 12:00AM