Modulus of Subgrade Reaction of Unreinforced and Geogrid-Reinforced Granular Fill Over Soft Clay
Publication: International Journal of Geomechanics
Volume 21, Issue 9
Abstract
In the present paper, the modulus of subgrade reaction or subgrade modulus for sand–clay layered soil (granular fill over clay) with or without geogrid reinforcement is determined under vertical loading by a series of model-scale plate load tests (PLTs). Various parameters such as thickness of the sand layer over clay, shape and width of the test plates, number of reinforcement layers, and spacing between two closely spaced plates (to simulate the interference effect of foundations) are included in the study. Five model plates with different aspect ratios (length to width ratio, L/B) are used to investigate the effect of aspect ratio and width of the plate on modulus of subgrade reaction for layered soil. The modulus of subgrade reaction for unreinforced soil increases significantly when the sand thickness increases over clay even if the thickness is more than twice the width of the test plate. However, marginal increment in modulus of subgrade reaction is observed when the sand thickness to plate width ratio is greater than 1.25 for geogrid-reinforced sand–clay layered soil. The maximum improvement in modulus of subgrade reaction due to inclusion of geogrid is observed when the thickness of the granular fill over soft clay is 0.75 times the width of the test plates. For an unreinforced bed, the modulus of subgrade reaction can be reduced up to 16% due to interference effect when the spacing (S) between the plates is less than 1.33 times the width of the plates. For reinforced sand–clay bed, 12% reduction in subgrade modulus can occur due to the interference effect. The subgrade modulus decreases with aspect ratio of the plates for both single and dual plate cases.
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References
AASHTO. 1993. AASHTO guide for design of pavement structures. Washington, DC: AASHTO.
BIS (Bureau of Indian Standards). 1979. Method of determination of modulus of subgrade reaction (k-value) of soils in field. IS 9214. New Delhi, India: BIS.
Black, J. A., V. Sivakumar, M. R. Madhav, and G. A. Hamill. 2007. “Reinforced stone columns in weak deposits: Laboratory model study.” J. Geotech. Geoenviron. Eng. 133 (9): 1154–1161. https://doi.org/10.1061/(ASCE)1090-0241(2007)133:9(1154).
Bowles, J. E. 1997. Foundation analysis and design. 5th ed. New York: McGraw Hill.
Chen, Q., and M. Abu-Farsakh. 2015. “Ultimate bearing capacity analysis of strip footings on reinforced soil foundation.” Soils Found. 55 (1): 74–85. https://doi.org/10.1016/j.sandf.2014.12.006.
Chen, Q., M. Abu-Farsakh, and R. Sharma. 2009. “Experimental and analytical studies of reinforced crushed limestone.” Geotext. Geomembr. 27 (5): 357–367. https://doi.org/10.1016/j.geotexmem.2009.03.002.
Dash, S. K. 2010. “Influence of relative density of soil on performance of geocell-reinforced sand foundations.” J. Mater. Civ. Eng. 22 (5): 533–538. https://doi.org/10.1061/(ASCE)MT.1943-5533.0000040.
Dash, S. K., and M. C. Bora. 2013. “Improved performance of soft clay foundations using stone columns and geocell-sand mattress.” Geotext. Geomembr. 41: 26–35. https://doi.org/10.1016/j.geotexmem.2013.09.001.
Dash, S. K., K. Rajagopal, and N. R. Krishnaswamy. 2001. “Strip footing on geocell reinforced sand beds with additional planar reinforcement.” Geotext. Geomembr. 19 (8): 529–538. https://doi.org/10.1016/S0266-1144(01)00022-X.
Dash, S. K., P. D. T. Reddy, and S. T. G. Raghukanth. 2008. “Subgrade modulus of geocell-reinforced sand foundations.” Proc. Inst. Civ. Eng. Ground Improv. 161 (2): 79–87. https://doi.org/10.1680/grim.2008.161.2.79.
Dash, S. K., S. Sireesh, and T. G. Sitharam. 2003. “Model studies on circular footing supported on geocell reinforced sand underlain by soft clay.” Geotext. Geomembr. 21 (4): 197–219. https://doi.org/10.1016/S0266-1144(03)00017-7.
Demir, A., A. Laman, A. Yildiz, and M. Ornek. 2013. “Large scale field tests on geogrid-reinforced granular fill underlain by clay soil.” Geotext. Geomembr. 38: 1–15. https://doi.org/10.1016/j.geotexmem.2012.05.007.
DIN (Deutsches Institut für Normung). 2001. Determining the deformation and strength characteristics of soil by plate loading tests. DIN 18134. Berlin: DIN.
Dinçer, İ. 2011. “Models to predict the deformation modulus and the coefficient of subgrade reaction for earth filling structures.” Adv. Eng. Software 42 (4): 160–171. https://doi.org/10.1016/j.advengsoft.2011.02.001.
El-Emam, M. M., and R. J. Bathurst. 2004. “Experimental design, instrumentation and interpretation of reinforced soil wall response using a shaking table.” Int. J. Phys. Modell. Geotech. 4 (4): 13–32. https://doi.org/10.1680/ijpmg.2004.040402.
Elsamee, W. N. A. 2013. “An experimental study on the effect of foundation depth, size and shape on subgrade reaction of cohessionless soil.” Sci. Res. Eng. 5 (10): 36744. https://doi.org/10.4236/eng.2013.510095.
El Sawwaf, M. A. 2009. “Experimental and numerical study of eccentrically loaded strip footings resting on reinforced sand.” J. Geotech. Geoenviron. Eng. 135 (10): 1509–1518. https://doi.org/10.1061/(ASCE)GT.1943-5606.0000093.
Ghosh, P., P. K. Basudhar, V. Srinivasan, and K. Kunal. 2015. “Experimental studies on interference of two angular footings resting on surface of two-layer cohesionless soil deposit.” Int. J. Geotech. Eng. 9 (4): 422–433. https://doi.org/10.1179/1939787914Y.0000000080.
Giroud, J. P., and L. Noiray. 1981. “Geotextile-Reinforced unpaved road design.” J. Geotech. Eng. Div. 107 (9): 1233–1254. https://doi.org/10.1061/AJGEB6.0001187.
Hegde, A. M., and T. G. Sitharam. 2015. “Effect of infill materials on the performance of geocell reinforced soft clay beds.” Geomech. Geoeng. 10 (3): 163–173. https://doi.org/10.1080/17486025.2014.921334.
Houlsby, G. T., and R. A. Jewell. 1990. “Design of reinforced unpaved roads for small rut depths.” In Vol. 1 of Proc., 4th Int. Conf. on Geotextiles, Geomembranes and Related Products, edited by G. den Hoedt, 171–176. Rotterdam, Netherlands: Belkama.
Hufenus, R., R. Rueegger, R. Banjac, P. Mayor, S. M. Springman, and R. Brönnimann. 2006. “Full-scale field tests on geosynthetic reinforced unpaved roads on soft subgrade.” Geotext. Geomembr. 24 (1): 21–37. https://doi.org/10.1016/j.geotexmem.2005.06.002.
Iai, S. 1989. “Similitude for shaking table tests on soil-structure-fluid model in 1g gravitational field.” Soils Found. 29 (1): 105–118. https://doi.org/10.3208/sandf1972.29.105.
IRC (Indian Road Congress). 2015. Guidelines for the design of plain jointed rigid pavements for highways. IRC-58. New Delhi, India: IRC.
IRC (Indian Road Congress). 2018. Code of guideline for the design of flexible pavement. IRC-37. New Delhi, India: IRC.
Ismael, N. F. 1987. “Coefficient of subgrade reaction for footings on desert sands.” Transp. Res. Rec. 1137: 82–89.
Kazi, M., S. K. Shukla, and D. Habibi. 2016. “Behaviour of an embedded footing on geotextile-reinforced sand.” Proc. Inst. Civ. Eng. Ground Improv. 169 (2): 120–133. https://doi.org/10.1680/grim.14.00022.
Khing, K. H., B. M. Das, V. K. Puri, S. C. Yen, and E. E. Cook. 1994. “Foundation on strong sand underlain by weak clay with geogrid at the interface.” Geotext. Geomembr. 13 (3): 199–206. https://doi.org/10.1016/0266-1144(94)90035-3.
Kouzer, K. M., and J. Kumar. 2010. “Ultimate bearing capacity of a footing considering the interference of an existing footing on sand.” Geotech. Geol. Eng. 28 (4): 457–470. https://doi.org/10.1007/s10706-010-9305-9.
Kumar, A., and S. Saran. 2003. “Closely spaced footings on geogrid-reinforced sand.” J. Geotech. Geoenviron. Eng. 129 (7): 660–664. https://doi.org/10.1061/(ASCE)1090-0241(2003)129:7(660).
Latha, G. M., and A. Somwanshi. 2009. “Effect of reinforcement form on the bearing capacity of square footings on sand.” Geotext. Geomembr. 27 (6): 409–422. https://doi.org/10.1016/j.geotexmem.2009.03.005.
Lee, J., and S. Jeong. 2016. “Experimental study of estimating the subgrade reaction modulus on jointed rock foundations.” Rock Mech. Rock Eng. 49 (6): 2055–2064. https://doi.org/10.1007/s00603-015-0905-9.
Lee, K. M., V. R. Manjunath, and D. M. Dewaikar. 1999. “Numerical and model studies of strip footing supported by a reinforced granular fill–soft soil system.” Can. Geotech. J. 36 (5): 793–806. https://doi.org/10.1139/t99-053.
Lin, P. S., L. W. Yang, and C. H. Juang. 1998. “Subgrade reaction and load–settlement characteristics of gravelly cobble deposits by plate-load tests.” Can. Geotech. J. 35 (5): 801–810. https://doi.org/10.1139/t98-044.
Love, J. P., H. J. Burd, G. W. E. Milligan, and G. T. Houlsby. 1987. “Analytical and model studies of reinforcement of a layer of granular fill on a soft clay subgrade.” Can. Geotech. J. 24 (4): 611–622. https://doi.org/10.1139/t87-075.
Lovisa, J., S. K. Shukla, and N. Sivakugan. 2010. “Behaviour of prestressed geotextile-reinforced sand bed supporting a loaded circular footing.” Geotext. Geomembr. 28 (1): 23–32. https://doi.org/10.1016/j.geotexmem.2009.09.002.
Milligan, G. W. E., R. A. Jewell, G. T. Houlsby, and H. J. Burd. 1989a. “A New approach to the design of unpaved roads: Part I.” Ground Eng. 22 (3): 25–29.
Milligan, G. W. E., R. A. Jewell, G. T. Houlsby, and H. J. Burd. 1989b. “A new approach to the design of unpaved roads: Part II.” Ground Eng. 22 (8): 37–42.
Moayed, R. Z., and M. A. Bolandi. 2012. “Determination of subgrade reaction modulus of two layered soil.” In Proc., 3rd Int. Conf. on New Developments in Soil Mechanics and Geotechnical Engineering, 165–170. Nicosia, TRNC Mersin 10-Turkey: The Turkish National Committee of Soil Mechanics and Geotechnical Engineering and Near East Univ.
Mohseni, S., M. Payan, and R. Jamshidi Chenari. 2018. “Soil–structure interaction analysis in natural heterogeneous deposits using random field theory.” Innov. Infrastruct. Solutions 3 (1): 62. https://doi.org/10.1007/s41062-018-0168-x.
Naeini, S. A., R. Ziaie Moayed, and F. Allahyari. 2014. “Subgrade reaction modulus (Ks) of clayey soils based on field tests.” J. Eng. Geol. 8 (1): 2021.
PCA (Portland Cement Association). 1984. Thickness design for concrete highway and street pavements. PCA EB109.01P. Skokie, IL: PCA.
Saha Roy, S., and K. Deb. 2015. “Effects of aspect ratio of rectangular foundations on subgrade modulus of soft soil.” In Int. Conf. on Soft Ground Engineering, Advances in Soft Ground Engineering, 571–579. Singapore: Research Publishing.
Saha Roy, S., and K. Deb. 2017a. “Effects of aspect ratio of footings on bearing capacity for geogrid-reinforced sand over soft soil.” Geosynth. Int. 24 (4): 362–382. https://doi.org/10.1680/jgein.17.00008.
Saha Roy, S., and K. Deb. 2017b. “Bearing capacity of rectangular footings on multilayer geosynthetic-reinforced granular fill over soft soil.” Int. J. Geomech. 17 (9): 04017069. https://doi.org/10.1061/(ASCE)GM.1943-5622.0000959.
Saha Roy, S., and K. Deb. 2018. “Closely spaced rectangular footings on sand over soft clay with geogrid at the interface.” Geosynth. Int. 25 (4): 412–426. https://doi.org/10.1680/jgein.18.00025.
Saha Roy, S., and K. Deb. 2019a. “Interference effect of closely spaced footings resting on granular fill over soft clay.” Int. J. Geomech. 19 (1): 04018181. https://doi.org/10.1061/(ASCE)GM.1943-5622.0001324.
Saha Roy, S., and K. Deb. 2019b. “Influence of footing interference on bearing capacity improvement for geogrid-reinforced sand bed underlain by soft clay.” In Geo Congress 2019: Earth Retaining Structures and Geosynthetics, Geotechnical Special Publication 306, edited by C. L. Meehan, S. Kumar, M. A. Pando, and J. T. Coe, 322–330. Reston, VA: ASCE.
Saha Roy, S., and K. Deb. 2020. “Effect of aspect ratio of footing on behavior of two closely-spaced footings on geogrid-reinforced sand.” Geotext. Geomembr. 48 (4): 443–453. https://doi.org/10.1016/j.geotexmem.2020.02.003.
Schmudderich, C., A. A. Lavasan, F. Tschuchnigg, and T. Wichtmann. 2020. “Bearing capacity of a strip footing placed next to an existing footing on frictional soil.” Soils Found. 60 (1): 229–238. https://doi.org/10.1016/j.sandf.2020.03.002.
Sharma, R., Q. Chen, M. Abu-Farsakh, and S. Yoon. 2009. “Analytical modeling of geogrid reinforced soil foundation.” Geotext. Geomembr. 27 (1): 63–72. https://doi.org/10.1016/j.geotexmem.2008.07.002.
Shukla, S. K. 2015. Concepts of geotechnical engineering. London: ICE Publishing.
Skempton, A. W. 1951. “The bearing capacity of clays.” In Building Research Congress, 180–189. London: ICE.
Tanyu, B. F., A. H. Aydilek, A. W. Lau, T. B. Edil, and C. H. Benson. 2013. “Laboratory evaluation of geocell-reinforced gravel subbase over poor subgrades.” Geosynth. Int. 20 (2): 47–61. https://doi.org/10.1680/gein.13.00001.
Terzaghi, K. 1943. Theoretical soil mechanics. New York: John Wiley & Sons.
Terzaghi, K. 1955. “Evaluation of conefficients of subgrade reaction.” Géotechnique 5 (4): 297–326. https://doi.org/10.1680/geot.1955.5.4.297.
Terzaghi, K., R. B. Peck, and G. Mesri. 1996. Soil mechanics in engineering practice. 3rd ed. New York: Wiley.
Vesic, A. S. 1973. “Analysis of ultimate loads of shallow foundations.” J. Soil Mech. Found. Div. 99 (1): 45–73. https://doi.org/10.1061/JSFEAQ.0001846.
Viswanadham, B. V. S., and D. König. 2004. “Studies on scaling and instrumentation of a geogrid.” Geotext. Geomembr. 22 (5): 307–328. https://doi.org/10.1016/S0266-1144(03)00045-1.
Walkenbach, T. N., J. Han, Z. Li, and R. L. Parsons. 2019. “Evaluation of composite subgrade reaction modulus of geosynthetic-stabilized recycled subbase over subgrade.” In Geo-Congress 2019: Geoenvironmental Engineering and Sustainability, Geotechnical Special Publication 312, edited by C. L. Meehan, S. Kumar, M. A. Pando, and J. T. Coe, 212–221. Reston, VA: ASCE.
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Published In
International Journal of Geomechanics
Volume 21 • Issue 9 • September 2021
Copyright
© 2021 American Society of Civil Engineers.
History
Received: Jun 25, 2020
Accepted: Apr 2, 2021
Published online: Jun 18, 2021
Published in print: Sep 1, 2021
Discussion open until: Nov 18, 2021
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