Experimental Investigation on Geosynthetic-Reinforced Soil Sections via California Bearing Ratio Test
Loose soils normally are of weak bearing capacity due to their structural nature. Being exposed to heavy traffic loads, they would fail in most cases. To tackle the aforementioned issue, geotechnical engineers have come up with different approaches; one of which is making use of geosynthetic-reinforced soil-aggregate systems. As these polymeric reinforcements have highlighted economic and environmentally-friendly features, they have become widespread in practice during the last decades. The present research investigates the efficiency of four different types of these reinforcements in increasing the bearing capacity of two-layered soil sections using a series California Bearing Ratio (CBR) test. The studied sections are comprised of a 10 cm-thick layer of no. 161 Firouzkooh sand (weak subgrade) and a 10 cm-thick layer of compacted aggregate materials (base course) classified as SP and GW according to the United Soil Classification System (USCS), respectively. The aggregate layer was compacted to the relative density (Dr) of 95% at the optimum water content (Wopt) of 6.5%. The applied reinforcements were including two kinds of geocomposites (type A and B), a geotextile, and a geogrid that were embedded at the interface of the lower and the upper layers of the soil-aggregate system. As the standard CBR mold was not appropriate in height for this study, the mold used for soaked CBR tests were utilized. To make a comparison between the results of stress-settlement behavior in the studied specimens, CBR values pertinent to the penetrations of 2.5 mm and 5 mm were considered. The obtained results demonstrated 21% and 24.5% increments in the amount of CBR value in the presence of geocomposite type A and geogrid, respectively. On the other hand, the effect of both geotextile and geocomposite type B on CBR values was generally insignificant in this research.
Digital Object Identifier (DOI): doi.org/10.5281/zenodo.3669178Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 129
 Abu-Farsakh, M., Chen, Q. and Sharma, R., 2013. An experimental evaluation of the behavior of footings on geosynthetic-reinforced sand. Soils and Foundations, 53(2), pp.335-348.
 Asha, M.N and Latha, G., 2010. ‘Modified CBR Tests on Geosynthetic Reinforced Soil-aggregate Systems’ 2010 Dec. 16–18, Indian Geotechnical Conference, 2010.
 Bergado, D.T., Youwai, S., Hai, C.N. and Voottipruex, P., 2001. Interaction of nonwoven needle-punched geotextiles under axisymmetric loading conditions. Geotextiles and Geomembranes, 19(5), pp.299-328.
 Miranda Carlos, D. and Pinho-Lopes, M. and Lurdes Lopes, M. (2016) ‘Effect of Geosynthetic Reinforcement Inclusion on the Strength Parameters and Bearing Ratio of a Fine Soil’ International Conference on Transportation Geotechnics. 143, pp. 34-41
 Motanelli, F., Zhao, A. and Rimoldi, P.(1997) ''Geosynthetics-Reinforced pavement system: testing and design'' Proceeding of Geosynthetics ''97, pp.549-604
 Subaida, E, A., Chandrakaran, S. and Sankar, N., “Laboratory Performance of Unpaved Roads Reinforced Woven Coir Geotextiles”, Geotextiles and Geomembranes, Vol. 27, pp. 204-210, 2009.
 ASTM D3080, “Standard test methods for direct shear test of soils under consolidated drained conditions,” American Society for Testing and Materials, 2011.
 ASTM D1241, “Standard Specification for Materials for Soil-Aggregate Subbase, Base, and Surface Courses,” American Society for Testing and Materials, 2015.
 ASTM D1557, “Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Modified Effort (56,000 ft-lbf/ft3 (2,700 kN-m/m3)),” American Society for Testing and Materials, 2012.
 ASTM D1883, “Standard Test Method for California Bearing Ratio (CBR) of Laboratory-Compacted Soils,” American Society for Testing and Materials, 2016.