Abstract
Reducing the cost of offshore platform construction is an urgent issue for marginal oilfield development. The offshore oil well structure includes a riser and a surface casing. The riser, surface casing and oil well cement can be considered special variable cross-section piles. Replacing or partially replacing the steel pipe pile foundation with a variable cross-section pile to provide the required bearing capacity for an offshore oil platform can reduce the cost of foundation construction and improve the economic efficiency of production. In this paper, the finite element analysis method is used to investigate the variable cross-section bearing mode of composite piles composed of a riser and a surface casing in saturated clay under a vertical load. The calculation formula of the bearing capacity at the variable section is derived based on the theory of spherical cavity expansion, the influencing factors of the bearing capacity coefficient Nc are revealed, and the calculation method of Nc is proposed. By comparing the calculation results with the results of the centrifuge test, the accuracy and applicability of the calculation method are verified. The results show that the riser composite pile has a rigid core in the soil under the variable cross-section, which increases the bearing capacity at the variable cross-section.
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References
American Petroleum Institute (API), 2014. Geotechnical and foundation design considerations, ANSI/API Recommended Practice 2GEO, American Petroleum Institute, Washington, DC, USA.
Fang, T., Liu, X.R., Geng, D.X., Luo, Z., Ji, X.T. and Zheng, M.X., 2012. Model testing study of vertical bearing behaviors for large diameter pile with variable cross-section (I), Rock and Soil Mechanics, 33(10), 2947–2952. (in Chinese)
Feng, J., Sun, R.J. and Li, J., 2009. The design and application of the minimum structure, Offshore Oil, 29(4), 99–103. (in Chinese)
Feng, X., Randolph, M.F., Gourvenec, S. and Wallerand, R., 2014. Design approach for rectangular mudmats under fully three-dimensional loading, Géotechnique, 64(1), 51–63.
Huang, L.W., Yang, F. and Zhang, J.J., 2009. Grouting connection between pile foundation and jacket for offshore wind turbine, Water Resources and Hydropower Engineering, 40(9), 39–42, 45. (in Chinese)
Hung, M., Jiang, S., Xu, D.X., Deng, T., Shangguan, X. and Fang, T., 2018. Load transfer mechanism and theoretical model of step tapered hollow pile with huge diameter, Chinese Journal of Rock Mechanics and Engineering, 37(10), 2370–2383. (in Chinese)
Liang, C., Liu, R., Wan, J., Guan, P. and Li, X.Y., 2018. Study on vertical bearing capacity of the riser composite pile in clay, Proceedings of ASME 2018 37th International Conference on Ocean, Offshore and Arctic Engineering, American Society of Mechanical Engineers Digital Collection.
Liu, R., 2001. Reliability Analysis and Stochastic Finite Element Study of Offshore Structure Foundations, Ph.D. Thesis, Tianjin University, Tianjin. (in Chinese)
Manandhar, S. and Yasufuku, N., 2013. Vertical bearing capacity of tapered piles in sands using cavity expansion theory, Soils and Foundations, 53(6), 853–867.
Meyerhof, G.G., 1951. The ultimate bearing capacity of foudations, Géotechnique, 2(4), 301–332.
Skempton, A.W., 1951. The bearing capacity of clays, Building Research Congress, London, 1, 180–189.
Vesic, A.S., 1972. Expansion of cavities in infinite soil mass, Journal of Soil Mechanics & Foundations Division, 98(SM3), 265–290.
Yan, S.W., Huo, Z.L., Sun, L.Q. and Liu, R., 2013. Study of working mechanism and bearing capacity behavior of bucket foundation for offshore wind turbine, Rock and Soil Mechanics, 34(7), 2036–2042. (in Chinese)
Zhai, H.Y., Yang, J., Zhou, J.L., Liu, S.J., Yang, L.P. and Cai, Z.S., 2008. Analysis and research of cementing strength tests between water isolation tube and soil, Oil Drilling & Production Technology, 30(2), 36–37, 41. (in Chinese)
Zhang, W.N., 1994. The most used simple platform in the Gulf of Mexico-“Seahorse” platform, Foreign Petroleum Machinery, 5(3), 22–25. (in Chinese)
Zuo, S.C., 1992. Concept of minimum offshore platform structure MOSS, China Offshore Platform, 7(6), 262–263. (in Chinese)
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Foundation item: This research was financially supported by the National Science Fund for Distinguished Young Scholars (Grant No. 51825904) and the National Science and Technology Major Project from the Ministry of Science and Technology (MOST) of China (Grant No. 2016ZX05058004-005).
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Liu, R., Liang, C. Study of the Bearing Capacity at the Variable Cross-Section of A Riser-Surface Casing Composite Pile. China Ocean Eng 35, 262–271 (2021). https://doi.org/10.1007/s13344-021-0023-2
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DOI: https://doi.org/10.1007/s13344-021-0023-2