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Combined Bearing Capacity of Spudcans on a Double Layer Deposit of Strong-Over-Weak Clays

  • Qilin Yin
  • Sheng Dong
Article
  • 14 Downloads

Abstract

An extreme sea storm process can lead to a jack-up rig under the combined loading condition of vertical load (V), horizontal load (H), and moment (M) to have stability problems. This paper presents the analysis of combined bearing capacities of a circular spudcan on layered clays with a strong layer overlying a comparatively weaker layer. Numerical models combined with displacement- based load tests, swipe tests, and constant ratio displacement probe tests are adopted to calculate the uniaxial bearing capacities, failure envelopes in combined V-H, V-M planes, and failure envelopes in a combined V-H-M load space, respectively. A parametric study on the effects of vertical load level V, the layer strength ratio su,t/su,b, and the hard layer thickness t1 on the bearing capacities is then performed. Results show that the vertical load level is a key factor that influences the values of H and M and the size of the H-M failure envelope. The existence of the underlying weak clay decreases the bearing capacities in all directions, and the vertical capacity Vult is affected more than the horizontal (Hult) and moment (Mult) capacities based on a single uniform deposit. The influence of the underlying weak clay on H-M failure envelope is mainly shown where H and M are coupled in the same direction. In contrast, little difference is observed when H and M are coupled in opposite directions.

Key words

combined bearing capacity circular spudcan layered clays vertical load level strength ratio hard layer thickness 

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Notes

Acknowledgements

The study was supported by the National Key R&D Program of China (No. 2016YFC0302301) and the National Natural Science Foundation of China (No. 51479183).

References

  1. Bransby, M. F., and Randolph, M. F., 1997. Shallow foundations subject to combined loadings. In: The Proceedings of the 9th International Conference on Computer Methods and Advances in Geomechanics. Wuhan, 3: 1947–1952.Google Scholar
  2. Bransby, M. F., and Randolph, M. F., 1998. Combined loading of skirted foundations. Géotechnique, 48 (5): 637–655.CrossRefGoogle Scholar
  3. Butterfield, R., Houlsby, G. T., and Gottardi, G., 1997. Standardised sign conventions and notation for generally loaded foundations. Géotechnique, 47 (4): 1051–1052.CrossRefGoogle Scholar
  4. Elkhatib, S., and Randolph, M. F., 2004. Finite element modelling of drag-in plate anchors in clay. In: The Proceedings of 9th International Symposium on Numerical Methods in Géomechanic. Ottawa, 541-547.Google Scholar
  5. Georgiadis, M., and Butterfield, R., 1988. Displacements of footings on sand under eccentric and inclined loads. Canadian Geotechnical Journal, 25 (2): 199–212.CrossRefGoogle Scholar
  6. Gourvenec, S., 2008. Effect of embedment on the undrained capacity of shallow foundations under general loading. Géotechnique, 58 (3): 177–186.CrossRefGoogle Scholar
  7. Gourvenec, S., and Randolph, M., 2003. Effect of strength nonhomogeneity on the shape of failure envelopes for combined loading of strip and circular foundations on clay. Géotechnique, 53 (6): 575–586.CrossRefGoogle Scholar
  8. Hansen, J. B., 1970. A revised and extended formula for bearing capacity. Bulletin No. 28. Danish Geotechnical Institute, Copenhagen, Denmark, 5-11.Google Scholar
  9. Hossain, M. S., and Randolph, M. F., 2009. New mechanismbased design approach for spudcan foundations on single layer clay. Journal of Geotechnical and Geoenvironmental Engineering, 135 (9): 1264–1274.CrossRefGoogle Scholar
  10. Jalal, M., Kimiaei, M., and Cassidy, M. J., 2016. Effects of irregular nonlinear ocean waves on the dynamic performance of an example jack-up structure during an extreme event. Marine Structures, 49: 148–162.CrossRefGoogle Scholar
  11. Kellezi, L., Kudsk, G., and Hofstede, H., 2008. Skirted footings capacity for combined loads and layered soil conditions. In: Proceedings of the Second British Geotechnical Association International Conference on Foundations. HIS Press, Dundee, 923-935.Google Scholar
  12. Loukidis, D., Chakraborty, T., and Salgado, R., 2008. Bearing capacity of strip footings on purely frictional soil under eccentric and inclined loads. Canadian Geotechnical Journal, 45 (6): 768–787.CrossRefGoogle Scholar
  13. Martin, C. M., and Houlsby, G. T., 2001. Combined loading of spudcan foundations on clay: Numerical modelling. Géotechnique, 51 (8): 687–699.CrossRefGoogle Scholar
  14. Martin, C. M., and Randolph, M., 2001. Applications of lower and upper bound theorems of plasticity to collapse of circular foundations. In: Proceedings of the 10th Interational Conference on Computer Methods and Advances in Geomechanics. Balkema, 1417-1428.Google Scholar
  15. Meyerhof, G. G., 1953. The bearing capacity of foundations under eccentric and inclined loads. In: Proceedings of 3rd International Conference on Soil Mechanics and Foundation Engineering. Zurich, 440-445.Google Scholar
  16. O’Neill, M. P., Bransby, M. F., and Randolph, M. F., 2003. Drag anchor fluke-soil interaction in clays. Canadian Geotechnical Journal, 40 (1): 78–94.CrossRefGoogle Scholar
  17. Patra, C., Behara, R., Sivakugan, N., and Das, B. M., 2012a. Ultimate bearing capacity of shallow strip foundation under eccentrically inclined load, Part I. International Journal of Geotechnical Engineering, 6 (3): 343–352.CrossRefGoogle Scholar
  18. Patra, C., Behara, R., Sivakugan, N., and Das, B. M., 2012b. Ultimate bearing capacity of shallow strip foundation under eccentrically inclined load, Part II. International Journal of Geotechnical Engineering, 6 (4): 507–514.CrossRefGoogle Scholar
  19. Qiu, G., and Henke, S., 2011. Controlled installation of spudcan foundations on loose sand overlying weak clay. Marine Structures, 24 (4): 528–550.CrossRefGoogle Scholar
  20. Salgado, R., Lyamin, A. V., Sloan, S. W., and Yu, H. S., 2004. Two- and three-dimensional bearing capacity of foundations in clay. Géotechnique, 54 (5): 297–306.CrossRefGoogle Scholar
  21. Simulia, D. S., 2012. Abaqus 6.12 documentation. Providence, Rhode Island, US.Google Scholar
  22. SNAME T&R 5-5A, 2008. Guidelines for site specific assessment of mobile jack-up units. Research Bulletin 5-5A. Society of Naval Architects and Marine Engineers, New Jersy, 98-125.Google Scholar
  23. 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.CrossRefGoogle Scholar
  24. Ukritchon, B., Andrew, J. W., and Scott, W. S., 1998. Undrained limit analyses for combined loading of strip footings on clay. Journal of Geotechnical and Geoenvironmental Engineering, 124 (3): 265–276.CrossRefGoogle Scholar
  25. Vulpe, C., Bienen B., and Gaudin, C., 2013. Predicting the undrained capacity of skirted spudcans under combined loading. Ocean Engineering, 74 (7): 178–188.CrossRefGoogle Scholar
  26. Wang, T., and Yan, M., 2016. Numerical study on keying of suction embedded plate anchors. Chinese Journal of Geotechnical Engineering, 38 (1): 118–123 (in Chinese with English abstract).Google Scholar
  27. Watson, P. G., and Randolph, M. F., 1997. A yield envelope design approach for caisson foundations in calcareous sediments. In: Proceedings of BOSS '97 Eighth International Conference on the Behaviour of Offshore Structures. Delft, 259-273.Google Scholar
  28. Yun, G., and Bransby, M. F., 2007. The horizontal-moment capacity of embedded foundations in undrained soil. Canadian Geotechnical Journal, 44 (4): 409–424.CrossRefGoogle Scholar
  29. Zhang, Y., Bienen, B., and Cassidy, M. J., 2012. Undrained bearing capacity of deeply buried flat circular footings under general loading. Journal of Geotechnical and Geoenvironmental Engineering, 138 (3): 385–397.CrossRefGoogle Scholar
  30. 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. Marine Structures, 24 (4): 459–477.CrossRefGoogle Scholar

Copyright information

© Science Press, Ocean University of China and Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.College of EngineeringOcean University of ChinaQingdaoChina

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