Effect of Lattice Leg and Sleeve on the Transient Vertical Bearing Capacity of Deeply Penetrated Spudcans in Clay
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 144, Issue 5
Abstract
In estimating the vertical bearing capacity of spudcan foundation, the effect of the realistic lattice leg extending from the top of the spudcan is often ignored. This paper examines both the lattice leg and sleeve effect on the transient vertical bearing capacity of a spudcan foundation using centrifuge model tests and the numerical method. The lattice legs and sleeves are characterized by two parameters, namely, the opening ratio and area ratio. The experimental results indicate that the use of lattice legs and sleeves tends to increase the spudcan bearing capacity, compared with a spudcan without legs, in both normally consolidated and overconsolidated clay deposits. This effect appears to vary with the opening ratios and area ratios of the leg. The finding shows that the lattice legs and sleeves affect the transient vertical bearing capacity in three ways. First, it restricts soil backflow to the region of the spudcan footprint. Second, a small amount of the sleeve friction resistance is induced during spudcan penetration. Finally, a larger vertical influence zone of the soil beneath the spudcan footing is mobilized. All these effects contribute to an increase in the transient spudcan bearing capacity. It may provide a way to enhance the bearing capacity and uplift resistance of spudcan foundation by changing the configuration of the existing lattice leg.
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Acknowledgments
The first author would like to acknowledge the research funding provided by the National Natural Science Foundation of China (No. 41530637) and the postdoctoral research funding provided by Jiangsu Province. The authors acknowledge the research funding provided by the Agency for Science Technology and Research and the Maritime and Port Authority of Singapore through the Centre for Offshore Research and Engineering under the Offshore Technology Research Program (Project No. 0821350042). The corresponding author would like to acknowledge the research funding provided by the National Natural Science Foundation of China (No. 51509025) and the China Postdoctoral Science Foundation (No. 2015M581988).
References
ABAQUS version 6.13 [Computer software]. Dassault Systèmes, Providence, RI.
API (American Petroleum Institute). (2007). “Design and analysis of stationkeeping systems for floating structures.”, Washington, DC.
BSI (British Standards Institution). (2012). “Petroleum and natural gas industries—Site-specific assessment of mobile offshore units—Part 1: Jack-ups.” ISO19905-1, London.
Cassidy, M. J. (2012). “Experimental observations of the penetration of spudcan footings in silt.” Geotechnique, 62(8), 727–732.
Chung, S. F., Randolph, M. F., and Schneider, J. A. (2006). “Effect of penetration rate on penetrometer resistance in clay.” J. Geotech. Geoenviron. Eng., 1188–1196.
Craig, W. H., and Chua, K. (1990). “Deep penetration of spud-can foundations on sand and clay.” Geotechnique, 40(4), 541–556.
Dean, E. T. R., James, R. G., Schofield, A. N., and Tsukamoto, Y. (1998). “Drum centrifuge study of three-leg jackup models on clay.” Geotechnique, 48(6), 761–785.
Endley, S. N., Rapoport, V., Thompson, P. J., and Baglioni, V. P. (1981). “Prediction of jack-up rig footing penetration.” Proc., Annual Offshore Technology Conf., Offshore Technology Conference, Houston, 285–296.
Finnie, I. M. S., and Randolph, M. F. (1994). “Punch-through and liquefaction induced failure of shallow foundations on calcareous sediments.” Int. Conf. on Behaviour of Offshore Structures BOSS’94, Elsevier, Amsterdam, Netherlands, 217–230.
Hossain, M. S., Hu, Y., Randolph, M. F., and White, D. J. (2005). “Limiting cavity depth for spudcan foundations penetrating clay.” Geotechnique, 55(9), 679–690.
Hossain, M. S., Mehryar, Z., Hu, Y., and Randolph, M. F. (2004). “Deep penetration of spudcan foundation into NC clay.” Proc., 23rd Int. Conf. on Offshore Mechanics and Arctic Engineering, ASME, New York, 329–335.
Hossain, M. S., and Randolph, M. F. (2009a). “Effect of strain rate and strain softening on the penetration resistance of spudcan foundations on clay.” Int. J. Geomech., 122–132.
Hossain, M. S., and Randolph, M. F. (2009b). “New mechanism-based design approach for spudcan foundations on single layer clay.” J. Geotech. Geoenviron. Eng., 1264–1274.
Houlsby, G. T., and Martin, C. M. (2003). “Undrained bearing capacity factors for conical footings on clay.” Geotechnique, 53(5), 513–520.
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.
Li, Y. P. (2014). “Lattice leg effects on the penetration and bearing behaviour of spudcan foundation.” Ph.D. thesis, National Univ. of Singapore, Singapore.
Li, Y. P., et al. (2017). “Effects of lattice leg on cavities and bearing capacity of deeply embedded spudcans in clay.” Geotechnique, 67(1), 1–17.
Li, Y. P., Lee, F. H., Goh, S. H., Yi, J. T., and Zhang, X. Y. (2012). “Centrifuge study of the effects of lattice leg on penetration resistance and bearing behavior of spudcan foundation in NC clay.” Proc., ASME 2012 31st Int. Conf. on Ocean, Offshore and Arctic Engineering OMAE2012, ASME, New York, 83137.
McClelland, B., Young, A. G., and Remmes, B. D. (1982). “Avoiding jack-up rig foundation failures.” Geotech. Eng., 13(2), 151–188.
Menzies, D., and Roper, R. (2008). “Comparison of jackup rig spudcan penetration methods in clay (OTC19545).” Offshore Technology Conf., Offshore Technology Conference, Houston.
Randolph, M. F., and Hope, S. (2004). “Effect of cone velocity on cone resistance and excess pore pressures.” Proc., Int. Symp. on Engineering Practice and Performance of Soil Deposits, Yodogawa Kogisha Co. Ltd., Osaka, Japan, 147–152.
Skempton, A. W. (1951). “The bearing capacity of clays.” Building Research Congress, Thomas Telford Ltd., London, 180–189.
SNAME (Society of Naval Architects and Marine Engineers). (2008). “Guidelines for site specific assessment of mobile jack-up units.” Jersey City, NJ.
Tho, K. K., Leung, C. F., Chow, Y. K., and Swaddiwudhipong, S. (2012). “Eulerian finite-element technique for analysis of jack-up spudcan penetration.” Int. J. Geomech., 64–73.
Yi, J. T., Goh, S. H., Lee, F. H., and Randolph, M. F. (2012a). “A numerical study of cone penetration in fine-grained soils allowing for consolidation effects.” Geotechnique, 62(8), 707–719.
Yi, J. T., Lee, F. H., Goh, S. H., Zhang, X. Y., and Wu, J. F. (2012b). “Eulerian finite element analysis of excess pore pressure generated by spudcan installation into soft clay.” Comput. Geotech., 42, 157–170.
Young, A. G., Remmes, B. D., and Meyer, B. J. (1984). “Foundation performance of offshore jack-up drilling rigs.” J. Geotech. Eng., 841–859.
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Information
Published In
Journal of Geotechnical and Geoenvironmental Engineering
Volume 144 • Issue 5 • May 2018
Copyright
©2018 American Society of Civil Engineers.
History
Received: Oct 18, 2016
Accepted: Oct 31, 2017
Published online: Feb 22, 2018
Published in print: May 1, 2018
Discussion open until: Jul 22, 2018
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