AUTOMATED CONE PENETROMETER: A NONDESTRUCTIVE FIELD TEST FOR SUBGRADE EVALUATION

The results of a comprehensive program for the design, development, and field testing of an automated cone penetrometer are presented as an effective method for evaluating the condition of subgrade soils. Using this newly developed device, as many as 70 locations were tested at a site during an 8-hr day. The current automated penetrometer has a penetration depth of 406 mm (16 in.) and provides penetration resistance output readings at incremental 25-mm (1-in.) depths. The use of the automated cone penetrometer device, including its unique features for field use as demonstrated in a comprehensive field evaluation program conducted at Kelly Air Force Base, San Antonio, Texas, is described along with the results of a California bearing ratio (CBR) versus cone index correlation study. Analysis of the field data revealed a linear correlation between CBR and cone index with a correlation coefficient of 0.875. A parallel laboratory testing program was conducted on three fine-grained subgrade soil types obtained from the same test site. The laboratory test results were consistent with those obtained in the field. The use of the automated cone penetrometer technique and the correlation of its results to the CBR proved to be an effective, efficient, and reliable method for evaluating the subgrade soils encountered at the Kelly AFB site. The automated cone penetrometer holds promise as a good assessment tool for developing a statistical representation of subgrade conditions for fine-grained soils on both new and existing projects.

• Record URL:
  • http://onlinepubs.trb.org/Onlinepubs/trr/1985/1022/1022-014.pdf
• Record URL:
  • https://scholar.google.com/scholar_lookup?title=AUTOMATED+CONE+PENETROMETER%3A+A+NONDESTRUCTIVE+FIELD+TEST+FOR+SUBGRADE+EVALUATION&author=S.+Khedr&author=D.+Kraft&author=J.+Jenkins&publication_year=1985
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/isbn/0309039118
• Supplemental Notes:
  • Publication of this paper sponsored by Committee on Exploration and Classification of Earth Materials. 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:
  • Khedr, Safwan A
  • Kraft, David C
  • Jenkins, James L
• Publication Date: 1985

Media Info

• Media Type: Print
• Features: Figures; Photos; References; Tables;
• Pagination: pp 108-115
• Monograph Title: Analysis and testing of granular bases and subbases
• Serial:
  • Transportation Research Record
  • Issue Number: 1022
  • Publisher: Transportation Research Board
  • ISSN: 0361-1981

Subject/Index Terms

• TRT Terms: Accuracy; California bearing ratio; Cone penetrometers; Depth; Field tests; Nondestructive tests; Pendulum tests; Penetrometers; Subgrade (Pavements)
• Subject Areas: Geotechnology; Highways; Pavements; I42: Soil Mechanics;

Filing Info

• Accession Number: 00457454
• Record Type: Publication
• ISBN: 0309039118
• Files: TRIS, TRB
• Created Date: Aug 31 1986 12:00AM