Form Approved
REPORT DOCUMENTATION PAGE
OMB No. 0704-0188
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OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS.
1. REPORT DATE (DD-MM-YY)
2. REPORT TYPE
3. DATES COVERED (From - To)
March 2001
Technical Report
4. TITLE AND SUBTITLE
5a. CONTRACT NUMBER
5b. GRANT NUMBER
Influence of Wheel Load Shape on Vertical Stress Reaching Subgrade through an Aggregate
Layer
5c. PROGRAM ELEMENT NUMBER
6. AUTHOR(S)
5d. PROJECT NUMBER
5e. TASK NUMBER
Karen S. Henry
5f. WORK UNIT NUMBER
7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)
8. PERFORMING ORGANIZATION REPORT
NUMBER
U.S. Army Engineer Research and Development Center
Cold Regions Research and Engineering Laboratory
72 Lyme Road
ERDC/CRREL TR-01-8
Hanover, New Hampshire 03755-1290
9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)
10. SPONSOR / MONITOR'S ACRONYM(S)
Office of the Chief of Engineers
Washington, DC
11. SPONSOR / MONITOR'S REPORT
NUMBER(S)
12. DISTRIBUTION / AVAILABILITY STATEMENT
Approved for public release; distribution is unlimited.
Available from NTIS, Springfield, Virginia 22161.
13. SUPPLEMENTARY NOTES
14. ABSTRACT
The U.S. Army design procedure to stabilize low-bearing-capacity soil with geotextiles is based on the assumption that the applied surface
load (the wheel load) is in the shape of a circle. The maximum vertical stress that reaches the subgrade through overlying aggregate is then
estimated on the basis of the assumption that the aggregate is an elastic, homogeneous, isotropic half-space and, therefore, that the stress
distribution can be estimated by using the Boussinesq method. To study the extent to which the shape of the applied load influences the
stress that reaches the subgrade through the aggregate layer, the maximum vertical stress at depth predicted by the Boussinesq method was
computed and compared for circular and rectangular loads. A comparison of the maximum vertical stress beneath circular and rectangular
loads as a function of depth indicated that the differences were insufficient to warrant a change in the design procedure for rectangular load
geometries that have length/width ratios of 3 or less, and, furthermore, that assuming that the load is circular is conservative. For length/
width ratios of 3 or less, the maximum vertical stress applied by a rectangle is at least 85% of that applied by a circle.
15. SUBJECT TERMS
Boussinesq
Wheel load
Stress distribution
16. SECURITY CLASSIFICATION OF:
17. LIMITATION OF
18. NUMBER
19a. NAME OF RESPONSIBLE PERSON
OF ABSTRACT
OF PAGES
a. REPORT
b. ABSTRACT
c. THIS PAGE
19b. TELEPHONE NUMBER (include area code)
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Standard Form 298 (Rev. 8-98)
]Prescribed by ANSI Std. 239.18
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