Failure Mechanism and Bearing Capacity of Footings Buried at Various Depths in Spatially Random Soil
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 141, Issue 2
Abstract
The objective of this paper is to demonstrate how the spatial variability of random soil affects the failure mechanism and the ultimate bearing capacity of foundations buried at various depths. A nonlinear finite-element analysis combined with random field theory is employed to explore the vertical capacity of foundations embedded at different depths in random soil. Different possibilities of shear failures resulting from spatial patterns of soil are demonstrated and are used to explain the significant discrepancy between the bearing capacity of the random soil and that of uniform soil. The effect of the spatial pattern of the soil on the development of shear planes is also investigated, with the coefficients of variation for the bearing capacity demonstrated to be closely related to the shear plane length. The results of the statistical variation in the bearing capacity are provided for different embedment depths, and these are also reported as the failure probability of the footing compared with the established uniform soil bearing capacity. Safety factors are proposed for foundations at different levels of failure probability. This study provides a thorough understanding of the failure mechanisms of footings in random soil, especially where structures can penetrate deeply into soil.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
This research was undertaken with support from the Australia-China Natural Gas Technology Partnership Fund and the Lloyd’s Register Foundation. Lloyd’s Register Foundation, a U.K.-registered charity and sole shareholder of Lloyd’s Register Group, invests in science, engineering, and technology for public benefit worldwide. This study comprises part of the activities of the Centre for Offshore Foundation Systems (COFS), currently supported as a node of the Australian Research Council Centre of Excellence for Geotechnical Science and Engineering.
References
ABAQUS 6.11 [Computer software]. Providence, RI, Dassault Systémes.
Ahmed, A., and Soubra, A.-H. (2012). “Probabilistic analysis of strip footings resting on a spatially random soil using subset simulation approach.” Georisk, 6(3), 188–201.
Al-Bittar, T., and Soubra, A.-H. (2013). “Bearing capacity of strip footings on spatially random soils using sparse polynomial chaos expansion.” Int. J. Numer. Anal. Methods Geomech., 37(13), 2039–2060.
Ang, A. H. S., and Tang, W. H. (2007). Probability concepts in engineering: Emphasis on applications in civil and environmental engineering, Wiley, New York.
Baecher, G. B., and Christian, J. T. (2003). Reliability and statistics in geotechnical engineering, Wiley, Chichester, U.K.
Cassidy, M. J., Quah, C. K., and Foo, K. S. (2009). “Experimental investigation of the reinstallation of spudcan footings close to existing footprints.” J. Geotech. Geoenviron. Eng., 474–486.
Cassidy, M. J., Uzielli, M., and Tian, Y. (2013). “Probabilistic combined loading failure envelopes of a strip footing on spatially variable soil.” Comput. Geotech., 49(Apr), 191–205.
Chiasson, P., Lafleur, J., Soulié, M., and Law, K. T. (1995). “Characterizing spatial variability of a clay by geostatistics.” Can. Geotech. J., 32(1), 1–10.
Ching, J., and Phoon, K.-K. (2013a). “Effect of element sizes in random field finite element simulations of soil shear strength.” Comput. Struct., 126(Sep), 120–134.
Ching, J., and Phoon, K.-K. (2013b). “Probability distribution for mobilised shear strengths of spatially variable soils under uniform stress states.” Georisk, 7(3), 209–224.
Cho, S. E., and Park, H. C. (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.
Craig, R. F. (2004). Craig’s soil mechanics, Taylor & Francis, New York.
Dasaka, S. M., and Zhang, L. M. (2012). “Spatial variability of in situ weathered soil.” Géotechnique, 62(5), 375–384.
Det Norske Veritas (DNV). (2012). “Design and installation of fluke anchors.” DNV-RP-E301, Høvik, Norway.
Endley, S. N., Rapoport, V., Thompson, P. J., and Baglioni, V. P. (1981). “Prediction of jack-up rig footing penetration.” Proc., 13th Offshore Technology Conf., Offshore Technology Conference, Houston, 285–296.
Fan, H., Huang, Q., and Liang, R. (2014). “Reliability analysis of piles in spatially varying soils considering multiple failure modes.” Comput. Geotech., 57(Apr), 97–104.
Fenton, G. A., and Griffiths, D. V. (2003). “Bearing-capacity prediction of spatially random soils.” Can. Geotech. J., 40(1), 54–65.
Fenton, G. A., and Griffiths, D. V. (2008). Risk assessment in geotechnical engineering, Wiley, Hoboken, NJ.
Fenton, G. A., and Vanmarcke, E. H. (1990). “Simulation of random fields via local average subdivision.” J. Eng. Mech., 1733–1749.
Gourvenec, S., and Randolph, M. (2003). “Effect of strength non-homogeneity on the shape of failure envelopes for combined loading of strip and circular foundations on clay.” Géotechnique, 53(6), 575–586.
Griffiths, D. V., and Fenton, G. A. (2001). “Bearing capacity of spatially random soil: The undrained clay Prandtl problem revisited.” Géotechnique, 51(4), 351–359.
Griffiths, D. V., Fenton, G. A., and Manoharan, N. (2002). “Bearing capacity of rough rigid strip footing on cohesive soil: Probabilistic study.” J. Geotech. Geoenviron. Eng., 743–755.
Hossain, M. S., and Randolph, M. F. (2009). “New mechanism-based design approach for spudcan foundations on single layer clay.” J. Geotech. Geoenviron. Eng., 1264–1274.
Hossain, M. S., and Randolph, M. F. (2010). “Deep-penetrating spudcan foundations on layered clays: Centrifuge tests.” Géotechnique, 60(3), 157–170.
Hu, Y., and Randolph, M. F. (1998). “A practical numerical approach for large deformation problems in soil.” Int. J. Numer. Anal. Methods Geomech., 22(5), 327–350.
Hu, Y., Randolph, M. F., and Watson, P. G. (1999). “Bearing response of skirted foundation on nonhomogeneous soil.” J. Geotech. Geoenviron. Eng., 924–935.
Huang, J., Lyamin, A. V., Griffiths, D. V., Krabbenhoft, K., and Sloan, S. W. (2013). “Quantitative risk assessment of landslide by limit analysis and random fields.” Comput. Geotech., 53(Sep), 60–67.
Kasama, K., and Whittle, A. J. (2011). “Bearing capacity of spatially random cohesive soil using numerical limit analyses.” J. Geotech. Geoenviron. Eng., 989–996.
Li, D.-Q., Qi, X.-H., Phoon, K.-K., Zhang, L.-M., and Zhou, C.-B. (2014). “Effect of spatially variable shear strength parameters with linearly increasing mean trend on reliability of infinite slopes.” Struct. Saf., 49(Jul), 45–55.
Lloret-Cabot, M., Fenton, G. A., and Hicks, M. A. (2014). “On the estimation of scale of fluctuation in geostatistics.” Georisk, 8(2), 129–140.
Menzies, D., and Lopez, C. R. (2011). “Four atypical jack-up rig foundation case histories.” Proc., 13th Int. Conf.: The Jack-up Platform—Design, Construction and Operation, City Univ., London.
Menzies, D., and Roper, R. (2008). “Comparison of jackup rig spudcan penetration methods in clay.” Proc., 40th Offshore Technology Conf., Offshore Technology Conference, Houston.
Merifield, R. S., Sloan, S. W., and Yu, H. S. (2001). “Stability of plate anchors in undrained clay.” Géotechnique, 51(2), 141–153.
Nobahar, A., and Popescu, R. (2000). “Spatial variability of soil properties—Effects on foundation design.” Proc., 53rd Canadian Geotechnical Conf., Vol. 2, Canadian Geotechnical Society, Richmond, BC, Canada, 1139–1144.
O’Neill, M. P., Bransby, M. F., and Randolph, M. F. (2003). “Drag anchor fluke-soil interaction in clays.” Can. Geotech. J., 40(1), 78–94.
Phoon, K.-K., and Kulhawy, F. H. (1999). “Characterization of geotechnical variability.” Can. Geotech. J., 36(4), 612–624.
Popescu, R., Deodatis, G., and Nobahar, A. (2005). “Effects of random heterogeneity of soil properties on bearing capacity.” Probab. Eng. Mech., 20(4), 324–341.
Randolph, M. F., Jamiolkowski, M. B., and Zdravkovic, L. (2004). “Load carrying capacity of foundations.” Proc., Skempton Memorial Conf. on Advances in Geotechnical Engineering, Thomas Telford, London, 207–240.
Rowe, R. K., and Davis, E. H. (1982). “The behaviour of anchor plates in clay.” Géotechnique, 32(1), 9–23.
Salgado, R., and Kim, D. (2014). “Reliability analysis of load and resistance factor design of slopes.” J. Geotech. Geoenviron. Eng., 57–73.
Taiebat, H. A., and Carter, J. P. (2000). “Numerical studies of the bearing capacity of shallow foundations on cohesive soil subjected to combined loading.” Géotechnique, 50(4), 409–418.
Uzielli, M., Vannucchi, G., and Phoon, K. K. (2005). “Random field characterisation of stress-normalised cone penetration testing parameters.” Géotechnique, 55(1), 3–20.
Wang, C. X., and Carter, J. P. (2002). “Deep penetration of strip and circular footings into layered clays.” Int. J. Geomech., 205–232.
Zhang, Y., Bienen, B., Cassidy, M. J., and Gourvenec, S. (2011). “The undrained bearing capacity of a spudcan foundation under combined loading in soft clay.” Mar. Struct., 24(4), 459–477.
Zhang, Y., Bienen, B., Cassidy, M. J., and Gourvenec, S. (2012). “Undrained bearing capacity of deeply buried flat circular footings under general loading.” J. Geotech. Geoenviron. Eng., 385–397.
Zhang, Y., Wang, D., Cassidy, M. J., and Bienen, B. (2014). “Effect of installation on the bearing capacity of a spudcan under combined loading in soft clay.” J. Geotech. Geoenviron. Eng., 04014029.
Information & Authors
Information
Published In
Journal of Geotechnical and Geoenvironmental Engineering
Volume 141 • Issue 2 • February 2015
Copyright
© 2014 American Society of Civil Engineers.
History
Received: Jan 10, 2014
Accepted: Sep 17, 2014
Published online: Oct 20, 2014
Published in print: Feb 1, 2015
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.