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| An analytical method for laterally loaded large-diameter steel pipe piles based on load-transfer curves |
| ZHAI Endi1，2，SHI Shigang1，HU Zhongbo3，XU Chengshun1 |
(1. Key Laboratory of Urban Security and Disaster Engineering，Beijing University of Technology，Beijing 100124，China；
2. Goldwind Science and Technology Co.，Ltd.，Beijing 100176，China；3. China Three Gorges Corporation Co.，
Ltd.，Beijing 100038，China) |
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Abstract Offshore turbines are often supported on large-diameter steel pipe monopoles. There is a significant effect of soil-added-resistance force caused by the rotation of the pile section of laterally loaded large-diameter steel pipe piles. The impact of the soil-added-resistance force on pile lateral capacity should be taken into account. A modified Winkler foundation beam model was proposed to model the lateral bearing loads of large-diameter steel pipe piles，in which the soil and the pile are respectively modeled by nonlinear springs and C1 beam elements considering the shear deformation. Assuming that the secant stiffness of the soil load transfer curves inside a pile element is linear，finite element formulas were deduced to develop a coupling method which can take into account the soil-added-resistance force caused by the rotation of the pile section，and a corresponding program was written. Two case studies were performed to verify the coupling method developed in this paper，and their computed results were compared with those obtained by the p-y method only considering the lateral nonlinear springs? effect. The results show that the coupling method can better predict the laterally loaded characteristics of the large-diameter steel pipe pile. The closer the deformation of the large-diameter steel monopile is to the rigid rotation，the more obvious the soil-added-resistance force caused by the rotation of the pile section. On the contrary，the soil-added-resistance force can be ignored while the deformation of the large-diameter steel pipe pile is close to the flexible deformation.
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2019, Vol. 38 
