Form Approved
REPORT DOCUMENTATION PAGE
OMB No. 0704-0188
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1. AGENCY USE ONLY (Leave blank)
2. REPORT DATE
3. REPORT TYPE AND DATES COVERED
June 1999
4. TITLE AND SUBTITLE
5. FUNDING NUMBERS
Geotextile Reinforcement of Low-Bearing-Capacity Soils:
WU: TO-007
Comparison of Two Design Methods Applicable to Thawing Soils
4A 161102AT4Z
6. AUTHORS
Karen S. Henry
7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)
8. PERFORMING ORGANIZATION
REPORT NUMBER
Special Report 99-7
U.S. Army Cold Regions Research and Engineering Laboratory
72 Lyme Road
Hanover, New Hampshire 03755
9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)
10. SPONSORING/MONITORING
AGENCY REPORT NUMBER
Office of the Chief of Engineers
Washington, DC 20314-1000
11. SUPPLEMENTARY NOTES
12a. DISTRIBUTION/AVAILABILITY STATEMENT
12b. DISTRIBUTION CODE
Approved for public release; distribution is unlimited.
Available from NTIS, Springfield, Virginia 22161
13. ABSTRACT (Maximum 200 words)
Thawing fine-grained soils are often saturated and have extremely low bearing capacity. Geosynthetics are used to
reinforce unsurfaced roads on weak, saturated soils and therefore are good candidates for use in stabilization of
thawing soils. To stabilize the soil, a geotextile is placed on it, then the geotextile is covered with aggregate. Design
involves selection of aggregate thickness and geotextile. There are two commonly used design techniques for
geotextile reinforcement of low-volume roads, and the Army uses one of them. The theory and use of the two
design methods for static loading (i.e., up to 100 vehicle passes) are presented and compared in this report. The
design method not used by the Army offers the potential to reduce aggregate thickness over the geotextile because
it accounts for the fact that the geotextile helps support the traffic load (when in tension) and confines the soil
between the wheels and the subgrade. However, this alternative method appears to be unconservative with re-
spect to stresses estimated at the subgrade surface. Thus, the current Army design technique should be used until
more research is conducted. In the meantime, straightforward design curves for Army 10- and 20-ton trucks as
well as vehicle loading and tire pressure information for a number of other vehicles are included in this report to
help make the current design method easy to use.
Future work should consider adopting a hybrid design method that provides realistic estimates of stresses at the
subgrade and accounts for the tensile properties of geotextiles. In addition, aggregates other than the high-quality
crushed rock that is inherently assumed by each design method should be accounted for in new design develop-
ment.
14. SUBJECT TERMS
15. NUMBER OF PAGES
Geosynthetics
Military vehicles
36
Reinforcement
16. PRICE CODE
Low-bearing-capacity soils
Thawing soils
17. SECURITY CLASSIFICATION
18. SECURITY CLASSIFICATION
19. SECURITY CLASSIFICATION
20. LIMITATION OF ABSTRACT
OF REPORT
OF THIS PAGE
OF ABSTRACT
UNCLASSIFIED
UNCLASSIFIED
UNCLASSIFIED
UL
Standard Form 298 (Rev. 2-89)
NSN 7540-01-280-5500
Prescribed by ANSI Std. Z39-18
298-102
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