Bearing Capacity of Strip Footings Seated on Unreinforced and Geosynthetic-Reinforced Granular Layers over Spatially Variable Soft Clay Deposits
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 149, Issue 6
Abstract
In the literature, the influence of spatial variability of the undrained shear strength of foundation soils on the bearing capacity of footings is limited to footings seated directly on the foundation. This is an unlikely arrangement in practice. This paper revisits the footing problem by considering a thin granular layer between a strip footing and soft foundation soil using analytical and stochastic numerical modeling. The analyses are extended to the case of a geosynthetic-reinforced granular layer and to the idealized case of no granular layer. The study shows that the probability that the ultimate bearing capacity for the footing is smaller than the deterministic design value is greater for all three scenarios with randomly uniform clay soil than for the same soil with isotropic or anisotropic spatial variability of strength at practical levels of reliability index (e.g., for a permanent footing). The reason for this outcome, which may appear counterintuitive, is explained. Design charts are provided to estimate the deterministic design bearing capacity of a rigid strip footing required to meet a range of target reliability index for the three footing scenarios examined in this study.
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Data Availability Statement
Some or all data, models, or code that support the findings of this study are available from the corresponding author upon reasonable request.
Acknowledgments
Financial support for this study was provided by the Natural Sciences and Engineering Research Council (NSERC) of Canada through Grant No. RGPIN-2018-04076 held by the second author. The assistance of N. Bozorgzadeh with the bootstrap code is gratefully acknowledged.
References
Allen, T. M., and R. J. Bathurst. 2019. “Geosynthetic reinforcement stiffness characterization for MSE wall design.” Geosynth. Int. 26 (6): 592–610. https://doi.org/10.1680/jgein.19.00041.
Allen, T. M., A. S. Nowak, and R. J. Bathurst. 2005. Calibration to determine load and resistance factors for geotechnical and structural design. Washington, DC: Transportation Research Board.
Basudhar, P. K., P. M. Dixit, A. Gharpure, and K. Deb. 2008. “Finite element analysis of geotextile-reinforced sand-bed subjected to strip loading.” Geotext. Geomembr. 26 (1): 91–99. https://doi.org/10.1016/j.geotexmem.2007.04.002.
Bathurst, R. J., and F. M. Ezzein. 2017. “Insights into geogrid-soil interaction using a transparent granular soil.” Geotech. Lett. 7 (2): 179–183. https://doi.org/10.1680/jgele.16.00191.
Bathurst, R. J., and S. Javankhoshdel. 2017. “Influence of model type, bias and input parameter variability on reliability analysis for simple limit states in soil-structure interaction problems.” Georisk 11 (1): 42–54. https://doi.org/10.1080/17499518.2016.1154160.
Bathurst, R. J., Y. Miyata, and T. M. Allen. 2020. “Deterministic and probabilistic assessment of margins of safety for internal stability of as-built PET strap reinforced soil walls.” Geotext. Geomembr. 48 (6): 780–792. https://doi.org/10.1016/j.geotexmem.2020.06.001.
Bathurst, R. J., and F. M. Naftchali. 2021. “Geosynthetic reinforcement stiffness for analytical and numerical modelling of reinforced soil structures.” Geotext. Geomembr. 49 (4): 921–940. https://doi.org/10.1016/j.geotexmem.2021.01.003.
Biswas, A., M. A. Ansari, S. K. Dash, and A. M. Krishna. 2015. “Behavior of geogrid reinforced foundation systems supported on clay subgrades of different strengths.” Int. J. Geosynth. Ground Eng. 1 (3): 1–10. https://doi.org/10.1007/s40891-015-0023-5.
Biswas, N., and P. Ghosh. 2019. “Bearing capacity factors for isolated surface strip footing resting on multi-layered reinforced soil bed.” Indian Geotech. J. 49 (1): 37–49. https://doi.org/10.1007/s40098-017-0293-z.
Burd, H. J., and C. J. Brocklehurst. 1990. “Finite element studies of the mechanics of reinforced unpaved roads.” In Vol. 1 of Proc., 4th Int. Conf. on Geotextiles, Geomembranes and Related Products, 217–221. Rotterdam, Netherlands: A. A. Balkema.
Burd, H. J., and S. Frydman. 1997. “Bearing capacity of plane-strain footings on layered soils.” Can. Geotech. J. 34 (2): 241–253. https://doi.org/10.1139/t96-106.
Burland, J. B., and M. C. Burbidge. 1985. “Settlement of foundations on sand and gravel.” Proc. Inst. Civ. Eng. 78 (6): 1325–1381. https://doi.org/10.1680/iicep.1985.1058.
Chakraborty, D., and J. Kumar. 2014. “Bearing capacity of strip foundations in reinforced soils.” Int. J. Geomech. 14 (1): 45–58. https://doi.org/10.1061/(ASCE)GM.1943-5622.0000275.
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.
Cho, S. E., and H. C. Park. 2010. “Effect of spatial variability of cross-correlated soil properties on bearing capacity of strip footing.” Int. J. Numer. Anal. Methods Geomech. 34 (1): 1–26. https://doi.org/10.1002/nag.791.
D’Appolonia, D. J., R. V. Whitman, and E. D’Appolonia. 1969. “Sand compaction with vibratory rollers.” J. Soil Mech. Found. Div. 95 (1): 263–284. https://doi.org/10.1061/JSFEAQ.0001221.
Das, B. M., K. H. Khing, and E. C. Shin. 1998. “Stabilization of weak clay with strong sand and geogrid at sand-clay interface.” Transp. Res. Rec. 1611 (1): 55–62. https://doi.org/10.3141/1611-07.
Demir, A., M. Laman, A. Yildiz, and M. Ornek. 2013. “Large scale field tests on geogrid-reinforced granular fill underlain by clay soil.” Geotext. Geomembr. 38 (Jun): 1–15. https://doi.org/10.1016/j.geotexmem.2012.05.007.
Demir, A., A. Yildiz, M. Laman, and M. Ornek. 2014. “Experimental and numerical analyses of circular footing on geogrid-reinforced granular fill underlain by soft clay.” Acta Geotech. 9 (4): 711–723. https://doi.org/10.1007/s11440-013-0207-x.
Dietrich, C. R., and G. N. Newsam. 1993. “A fast and exact method for multidimensional Gaussian stochastic simulations.” Water Resour. Res. 29 (8): 2861–2869. https://doi.org/10.1029/93WR01070.
Efron, B., and R. J. Tibshirani. 1993. An introduction to the bootstrap. Boca Raton, FL: Chapman and Hall/CRC Press.
Fannin, R. J., and O. Sigurdsson. 1996. “Field observations on stabilization of unpaved roads with geosynthetics.” J. Geotech. Eng. 122 (7): 544–553. https://doi.org/10.1061/(ASCE)0733-9410(1996)122:7(544).
Fenton, G. A., X. Zhang, and D. V. Griffiths. 2007. “Reliability of shallow foundations designed against bearing failure using LRFD.” Georisk 1 (4): 202–215. https://doi.org/10.1080/17499510701812844.
Giroud, J. P., C. Ah-Line, and R. Bonaparte. 1984. “Design of unpaved roads and trafficked areas with geogrids.” In Polymer grid reinforcement, 116–127. London: Thomas Telford.
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.
Griffiths, D. V., and G. A. Fenton. 2001. “Bearing capacity of spatially random soil: The undrained clay Prandtl problem revisited.” Géotechnique 51 (4): 351–359. https://doi.org/10.1680/geot.2001.51.4.351.
Griffiths, D. V., G. A. Fenton, and N. Manoharan. 2002. “Bearing capacity of rough rigid strip footing on cohesive soil: Probabilistic study.” J. Geotech. Geoenviron. Eng. 128 (9): 743–755. https://doi.org/10.1061/(ASCE)1090-0241(2002)128:9(743).
Hanna, A. M., and G. G. Meyerhof. 1980. “Design charts for ultimate bearing capacity of foundations on sand overlying soft clay.” Can. Geotech. J. 17 (2): 300–303. https://doi.org/10.1139/t80-030.
Hatami, K., and R. J. Bathurst. 2006. “A numerical model for reinforced soil segmental walls under surcharge loading.” J. Geotech. Geoenviron. Eng. 132 (6): 673–684. https://doi.org/10.1061/(ASCE)1090-0241(2006)132:6(673).
Holtz, R. D., W. D. Kovacs, and T. C. Sheahan. 1981. An introduction to geotechnical engineering Vol. 733. Englewood Cliffs, NJ: Prentice-Hall.
Huang, B., R. J. Bathurst, and K. Hatami. 2009. “Numerical study of reinforced soil segmental walls using three different constitutive soil models.” J. Geotech. Geoenviron. Eng. 135 (10): 1486–1498. https://doi.org/10.1061/(ASCE)GT.1943-5606.0000092.
Huang, C. C., and F. Y. Menq. 1997. “Deep-footing and wide-slab effects in reinforced sandy ground.” J. Geotech. Geoenviron. Eng. 123 (1): 30–36. https://doi.org/10.1061/(ASCE)1090-0241(1997)123:1(30).
Huang, J., and D. V. Griffiths. 2015. “Determining an appropriate finite element size for modelling the strength of undrained random soils.” Comput. Geotech. 69 (Sep): 506–513. https://doi.org/10.1016/j.compgeo.2015.06.020.
Jamshidi Chenari, R., and R. J. Bathurst. 2023. “Influence of geosynthetic stiffness on bearing capacity of strip footings seated on thin reinforced granular layers over undrained soft clay.” Geotext. Geomembr. 51 (1): 43–55. https://doi.org/10.1016/j.geotexmem.2022.09.006.
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.
Kotake, N., F. Tatsuoka, T. Tanaka, M. S. A. Siddiquee, and C. C. Huang. 2001. “FEM simulation of the bearing capacity of level reinforced sand ground subjected to footing load.” Geosynth. Int. 8 (6): 501–549. https://doi.org/10.1680/gein.8.0205.
Kroese, D. P., and Z. I. Botev. 2015. “Spatial process simulation.” In Stochastic geometry, spatial statistics and random fields, 369–404. Geneva: Springer.
Kumar, J., and J. P. Sahoo. 2013. “Bearing capacity of strip foundations reinforced with geogrid sheets by using upper bound finite-element limit analysis.” Int. J. Numer. Anal. Methods Geomech. 37 (18): 3258–3277. https://doi.org/10.1002/nag.2189.
Laman, M., A. Yildiz, M. Ornek, and A. Demir. 2012. “Field test of circular footings on reinforced granular fill layer overlying a clay bed.” Geotech. Test. J. 35 (4): 575–585. https://doi.org/10.1520/GTJ103512.
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.
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.
Luo, N., and R. J. Bathurst. 2018. “Deterministic and random FEM analysis of full-scale unreinforced and reinforced embankments.” Geosynth. Int. 25 (2): 164–179. https://doi.org/10.1680/jgein.17.00040.
Meyerhof, G. G. 1974. “Ultimate bearing capacity of footings on sand layer overlying clay.” Can. Geotech. J. 11 (2): 223–229. https://doi.org/10.1139/t74-018.
Michalowski, R. L. 2004. “Limit loads on reinforced foundation soils.” J. Geotech. Geoenviron. Eng. 130 (4): 381–390. https://doi.org/10.1061/(ASCE)1090-0241(2004)130:4(381).
Michalowski, R. L., and L. Shi. 1995. “Bearing capacity of footings over two-layer foundation soils.” J. Geotech. Eng. 121 (5): 421–428. https://doi.org/10.1061/(ASCE)0733-9410(1995)121:5(421).
Otani, J., H. Ochiai, and K. Yamamoto. 1998. “Bearing capacity analysis of reinforced foundations on cohesive soil.” Geotext. Geomembr. 16 (4): 195–206. https://doi.org/10.1016/S0266-1144(98)00005-3.
Prasad, B. D., C. Hariprasad, and B. Umashankar. 2016. “Load-settlement response of square footing on geogrid reinforced layered granular beds.” Int. J. Geosynth. Ground Eng. 2 (4): 1–10. https://doi.org/10.1016/S0266-1144(98)00005-3.
Ranjbar Pouya, K., N. Zhalehjoo, and R. Jamshidi Chenari. 2014. “Influence of random heterogeneity of cross-correlated strength parameters on bearing capacity of shallow foundations.” Indian Geotech. J. 44 (4): 427–435. https://doi.org/10.1007/s40098-013-0096-9.
Saha Roy, S., and K. Deb. 2017a. “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. 2017b. “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.
Salimi Eshkevari, S., A. J. Abbo, and G. Kouretzis. 2019. “Bearing capacity of strip footings on sand over clay.” Can. Geotech. J. 56 (5): 699–709. https://doi.org/10.1139/cgj-2017-0489.
Scavuzzo, R. 2000. “Construction quality control testing of compacted fills: Optimum moisture-density values.” In Constructing and controlling compaction of earth fills, edited by D. W. Shanklin, K. R. Rademacher, and J. R. Talbots. West Conshohocken, PA: ASTM.
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.
Shiau, J. S., A. V. Lyamin, and S. W. Sloan. 2003. “Bearing capacity of a sand layer on clay by finite element limit analysis.” Can. Geotech. J. 40 (5): 900–915. https://doi.org/10.1139/t03-042.
Terzaghi, K., R. B. Peck, and G. Mesri. 1996. Soil mechanics in engineering practice. 3rd ed. New York: Wiley.
Tran, V. D. H., M. A. Meguid, and L. E. Chouinard. 2015. “Three-dimensional analysis of geogrid-reinforced soil using a finite-discrete element framework.” Int. J. Geomech. 15 (4): 04014066. https://doi.org/10.1061/(ASCE)GM.1943-5622.0000410.
Yu, Y., R. J. Bathurst, and T. M. Allen. 2016a. “Numerical modelling of the SR-18 geogrid reinforced modular block retaining walls.” J. Geotech. Geoenviron. Eng. 142 (5): 04016003. https://doi.org/10.1061/(ASCE)GT.1943-5606.0001438.
Yu, Y., I. P. Damians, and R. J. Bathurst. 2015. “Influence of choice of FLAC and PLAXIS interface models on reinforced soil-structure interactions.” Comput. Geotech. 65 (Apr): 164–174. https://doi.org/10.1016/j.compgeo.2014.12.009.
Yu, Y., N. Luo, and R. J. Bathurst. 2016b. “Soil statistical characteristics using numerically generated random fields for probability analysis of geosynthetic-reinforced soil foundations.” In Proc., 69th Canadian Geotechnical Conf. Vancouver, BC, Canada: Canadian Geotechnical Society.
Zhang, L., W. H. Tang, and C. W. W. Ng. 2001. “Reliability of axially loaded driven pile groups.” J. Geotech. Geoenviron. Eng. 127 (12): 1051–1060. https://doi.org/10.1061/(ASCE)1090-0241(2001)127:12(1051).
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Journal of Geotechnical and Geoenvironmental Engineering
Volume 149 • Issue 6 • June 2023
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© 2023 American Society of Civil Engineers.
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Received: Mar 17, 2022
Accepted: Jan 4, 2023
Published online: Mar 28, 2023
Published in print: Jun 1, 2023
Discussion open until: Aug 28, 2023
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