Performance of Triangular Aperture Geogrid-Reinforced Base Courses over Weak Subgrade under Cyclic Loading
Publication: Journal of Materials in Civil Engineering
Volume 25, Issue 8
Abstract
Geogrid (uniaxial or biaxial) is one type of geosynthetics that has been successfully used in slopes, walls, roads, and other applications. The main application of biaxial geogrid is to stabilize soft subgrade and reinforce weak base courses by providing lateral confinement. The confinement due to the interaction between aggregates and the ribs of biaxial geogrid depends on the geometry properties of the geogrid, such as rib shape and apertures size, the stiffness of the ribs, and the properties of aggregates. Research has shown that biaxial geogrid cannot provide uniform tensile resistance in all directions. To overcome this problem, a geogrid product with triangular apertures was developed and introduced into the market. Recent studies showed that the triangular aperture geogrid can provide nearly uniform tensile resistance in all directions and is more efficient in improving the performance of reinforced bases as compared with biaxial geogrid. However, the performance of triangular aperture geogrid-reinforced bases under dynamic loading and the influence of base course thickness on the confinement effect of triangular aperture geogrids have not been well evaluated. In this study, unreinforced and triangular aperture geogrid-reinforced bases at different thicknesses over a weak subgrade were constructed in a large geotechnical testing box () at the University of Kansas and tested under cyclic loading. During the tests, surface deformations and vertical stresses at the interface between the base and the subgrade were monitored. The test results indicated that triangular aperture geogrids reduced permanent deformation and maximum vertical stress at the interface as compared with the unreinforced bases. The geogrids improved the performance of the aggregate bases at different thicknesses. The benefit became more pronounced when a heavier-duty geogrid was used. The back-calculations from the test data showed that the stress distribution angle and the modulus ratio of base course to subgrade decreased with an increase of the load cycles. The stress distribution angle increased with the increase of the base thickness. The vertical stress distributions were compared with the computed distribution by the layered linear elastic theory. These test data provide the basis for the development of a design method for triangular aperture geogrid-reinforced bases over weak subgrade in the future.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
This research project was sponsored by Tensar International. Mr. Joseph Cavanaugh, vice-president of global technology and Mr. Nicholas Reck and Dr. Mark Wayne, the application technology managers at Tensar, have provided great help and technical guidance to this study. Mr. Howard Jim Weaver, the lab supervisor in the Department of Civil, Environmental, and Architectural Engineering (CEAE) at the University of Kansas (KU), designed, fabricated, and installed the loading system used for this study. Mr. Milad Jowkar, a then-undergraduate student in the CEAE Department at KU, provided great assistance to the laboratory tests. All the above support is greatly appreciated.
References
Brown, S. F., Kwan, J., and Thom, N. H. (2007). “Identifying the key parameters that influence geogrid reinforcement of railway ballast.” Geotext. Geomembr., 25(6), 326–335.
Chen, Q., Abu-Farsakh, M., and Tao, M. (2009). “Laboratory evaluation of geogrid base reinforcement and corresponding instrumentation program.” Geotech. Test. J., 32(6), 516–525.
Das, B. M., and Shin, E. C. (1994). “Strip foundation on geogrid-reinforced clay: behavior under cyclic loading.” Geotext. Geomembr., 13(10), 657–666.
Dong, Y.-L., Han, J., and Bai, X.-H. (2010a). “Bearing capacities of geogrid-reinforced sand bases under static loading.” Proc., GeoShanghai Int. Conf. 2010, Ground Improvement and Geosynthetics, Geotechnical Special Publication No. 207, A. J. Puppala, J. Huang, J. Han, and L. R. Hoyos, eds., ASCE, Reston, VA, 275–281.
Dong, Y.-L., Han, J., and Bai, X.-H. (2010b). “A numerical study on stress-strain responses of biaxial geogrids under tension at different directions.” Proc., GeoFlorida 2010: Advances in Analysis, Modeling & Design, Geotechnical Special Publication No. 199, ASCE, Reston, VA, 2551–2560.
Dong, Y.-L., Han, J., and Bai, X.-H. (2011). “Numerical analysis of tensile behavior of geogrids with rectangular and triangular apertures.” Geotext. Geomembr., 29(2), 83–91.
Federal Highway Administration (FHWA). (2008). “Geosynthetic design and construction guidelines reference manual.”, U.S. Dept. of Transportation, Federal Highway Administration, Washington, DC.
Gabr, M. (2001). “Cyclic plate loading tests on geogrid reinforced roads.” Research Rep. to Tensar Earth Technologies, Inc., North Carolina State Univ., Raleigh, NC.
Giroud, J. P. (2009). “An assessment of the use of geogrids in unpaved roads and unpaved areas.” Proc., Jubilee Symp. on Polymer Geogrid Reinforcement Conf., Tensar, Blackburn, UK.
Giroud, J. P., and Han, J. (2004a). “Design method for geogrid-reinforced unpaved roads. I: Development of design method.” J. Geotech. Geoenviron. Eng., 130(8), 775–786.
Giroud, J. P., and Han, J. (2004b). “Design method for geogrid-reinforced unpaved roads. II. Calibration and applications.” J. Geotech. Geoenviron. Eng., 130(8), 787–797.
Haas, R., Wall, J., and Carroll, R. G. (1988). “Geogrid reinforcement of granular bases in flexible pavements.”, Transportation Research Board, Washington DC, 19–27.
Han, J., and Bhandari, A. (2010). “The influence of geogrid aperture size on the behavior of reinforced granular bases.” Proc., Int. Symp. on Geomechanics and Geotechnics: From Micro to Macro, M. Jiang, F. Liu, and M. Bolton, eds., CRC Press, Bova Raton, FL, 683–687.
Lawton, E. C. (1995). “Section 5A: Nongrouting techniques.” Practical foundation engineering handbook, R. W. Brown, ed., McGraw-Hill, New York, 5.3–5.4.
Love, J. P. (1984). “Model testing of geogrids in unpaved roads.” Doctoral dissertation, Univ. of Oxford, Oxford, UK.
Perkins, S. W. (1999). “Geosynthetic reinforcement of flexible pavements: Laboratory based pavement test sections.”, Montana Dept. of Transportation, Helena, MT, 140.
Qian, Y., Han, J., Pokharel, S. K., and Parsons, R. L. (2011a). “Determination of resilient modulus of subgrade using cyclic plate loading tests.” Proc., GeoFrontiers 2011: Advances in Geotechnical Engineering, Geotechnical Special Publication No. 211, J. Han and D. E. Alzamora, eds., ASCE, Reston, VA.
Qian, Y., Han, J., Pokharel, S. K., and Parsons, R. L. (2011b). “Stress analysis on triangular aperture geogrid-reinforced bases over weak subgrade under cyclic loading-an experimental study.” Proc., 10th Int. Conf. on Low-Volume Roads, Transportation Research Board, Washington, DC, 83–91.
Qian, Y., Tutumluer, E., and Huang, H. (2011c). “A validated discrete element modeling approach for studying geogrid-aggregate reinforcement mechanisms.” Proc., GeoFrontiers 2011: Advances in Geotechnical Engineering, Geotechnical Special Publication No. 211, J. Han and D. E. Alzamora, eds., ASCE, Reston, VA.
Sigurdsson, O. (1991). “Geosynthetic stabilization of unpaved roads on soft ground: A field evaluation.” M.S. thesis, Univ. of British Columbia, Vancouver, Canada.
Watts, K., and Jenner, C. (2008). “Large-scale laboratory assessment of geogrids to reinforce granular working platforms.” Proc., EuroGeo4: 4th European Geosynthetics Conf. (CD), N. Dixon, ed., International Geosynthetics Society.
Webster, S. L. (1992). “Geogrid reinforced base courses for flexible pavements for light aircraft: Test section construction, behavior under traffic, laboratory tests, and design criteria.”, U.S. Department of Transportation and Federal Aviation Administration, Washington, DC, 91.
White, D. J., Vennapusa, P. K. R., Gieselman, H. H., Douglas, S. C., Zhang, J., and Wayne, M. H. (2011). “In-ground dynamic stress measurements for geosynthetic reinforced subgrade/subbase.” Proc., GeoFrontiers 2011: Advances in Geotechnical Engineering, Geotechnical Special Publication No. 211, J. Han and D. E. Alzamora, eds., ASCE, Reston, VA.
Information & Authors
Information
Published In
Journal of Materials in Civil Engineering
Volume 25 • Issue 8 • August 2013
Pages: 1013 - 1021
Copyright
© 2013 American Society of Civil Engineers.
History
Received: Dec 12, 2011
Accepted: Jul 24, 2012
Published online: Aug 27, 2012
Discussion open until: Jan 27, 2013
Published in print: Aug 1, 2013
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.