Field Tests of Offshore Driven Piles Subjected to Lateral Monotonic and Cyclic Loads in Soft Clay

Zhu, Bin; Zhu, Zhoujie; Li, Tao; Liu, Jinchao; Liu, Yanfeng

doi:10.1061/(asce)ww.1943-5460.0000399

Cited by 50 publications

(16 citation statements)

References 20 publications

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“…(3) The API p-y curve significantly underestimates the ultimate soil reaction of soft clays and the degree of the underestimation increases as the soil depth increases; it also significantly underestimates the initial stiffness of the soft clays. These findings are supported by previous research results [12,15]. (4) A new p-y model with variable parameters A and B was proposed that is more versatile and offers wider applicability to represent different soft clay and pile diameters.…”

Section: Main Conclusionsupporting

confidence: 85%

“…Rathod et al [14] developed new p-y curves for piles located on crests of soft clay with different sloping ground surfaces under static lateral loading by carrying out a series of laboratory model tests. Zhu et al [15] modified the hyperbolic tangent p-y curve by introducing an additional constant and verified its rationality using the field tests of offshore driven piles. Xu et al [16] found that the hyperbolic method yields larger prediction errors than the API method and proposed a modified p-y approach based on field measurements.…”

Section: Introductionmentioning

confidence: 99%

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A New p–y Curve for Laterally Loaded Large-Diameter Monopiles in Soft Clays

Wang

Cheng

et al. 2022

Sustainability

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In harsh offshore environmental conditions, the monopile foundations supporting offshore wind turbines must be designed for lateral loads such as winds, waves, and currents. The Beam on Nonlinear Winkler Foundation (BNWF) method has been widely used because of its clear concept and lower calculation cost. The selection of a reasonable p–y curve is critical to the calculation accuracy of this method. This paper clarified the defects of widely used API p–y curves for soft clays and then proposed a new p–y curve with better versatility and applicability. The suitability of the proposed p–y curve was validated by comparing it with the calculation results from the three-dimensional finite element method (3D FEM). Compared with the API p–y curve, the proposed p–y curve can better predict the lateral behavior of large-diameter piles in soft clays, such as the load–displacement curve of the pile head, lateral deflection profile, and bending moment profile. The research findings can provide guidance for the design of monopile foundations supporting offshore wind turbines in soft clays.

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Section: Main Conclusionsupporting

confidence: 85%

Section: Introductionmentioning

confidence: 99%

A New p–y Curve for Laterally Loaded Large-Diameter Monopiles in Soft Clays

Wang

Cheng

et al. 2022

Sustainability

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“…This has for instance been observed in field tests with up to one thousand lateral load cycles on piles (diameters D ¼ 0:273 m and D ¼ 1:22 m) in stiff overconsolidated clay [22]. Similar results were obtained in recent field tests on monopile foundations with a diameter of 2.2 m in soft clay reported in [91] as well as in the pioneer works of Matlock [47] (in soft clay) and Reese et al [60] (in heavily overconsolidated clay). In [77] a strong degradation of the lateral stiffness of the pile (D ¼ 0:8 m, founded in soft clay) was observed during the cyclic loading as soon as the magnitude of the load was larger than a certain threshold level.…”

Section: Piles In Clay Subjected To Cyclic Loadingsupporting

confidence: 84%

A high-cycle accumulation model for clay and its application to monopile foundations

et al. 2022

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A high-cycle accumulation (HCA) model predicting the accumulation of permanent strain or excess pore water pressure in clay under a large number of load cycles is presented. Data from an extensive laboratory testing program on kaolin under undrained cyclic loading has been analysed for that purpose. The influence of strain amplitude, void ratio, stress ratio, overconsolidation ratio and loading frequency on the accumulation rates is considered in the constitutive equations of the HCA model. The proposed model is validated first by the simulation of element tests. Subsequently, its application to offshore wind turbine foundations under long-term lateral cyclic loading is presented by the back-analysis of a centrifuge test on a monopile in soft clay. The results are in good accordance with the measurements in terms of pile displacement and bending moment versus number of applied cycles. It is concluded that the proposed model is feasible to describe the long-term behaviour of clay subjected to high-cyclic loading.

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“…Existing research results [4][5][6][7][8] are difficult to meet the needs of engineering practice. In particular, the design basis for monopile bearing capacity in API and DNV specifications [9,10] are derived from the test data of small-diameter pile foundation [11,12], and the size effect significantly affects the bearing capacity of pile foundation [13], which is not well applicable to large-diameter monopiles.…”

Section: Introductionmentioning

confidence: 99%

Study on time effect of bearing capacity of Offshore Large Diameter Monopiles

Yang

Chen²,

Bie

et al. 2022

CEJ

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In order to improve the evaluation ability of bearing capacity of offshore large-diameter monopile, the initial high strain detection and repeated high strain detection with an interval of 10-84 days were carried out on 6 large-diameter monopiles with a diameter of 7.2m-7.4m in the offshore wind field dominated by cohesive soil layer. The results show that the time-dependent increase of tip resistance, pile side resistance and total resistance of large-diameter monopiles in the same offshore wind farm has great discreteness, and the axial force increment of pile has a consistent change trend. This paper puts forward the prediction interval of 95% guarantee rate of bearing capacity increment of offshore large-diameter single pile based on depth, which provides a basis for the design of large-diameter monopile.

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Field Tests of Offshore Driven Piles Subjected to Lateral Monotonic and Cyclic Loads in Soft Clay

Cited by 50 publications

References 20 publications

A New p–y Curve for Laterally Loaded Large-Diameter Monopiles in Soft Clays

A New p–y Curve for Laterally Loaded Large-Diameter Monopiles in Soft Clays

A high-cycle accumulation model for clay and its application to monopile foundations

Study on time effect of bearing capacity of Offshore Large Diameter Monopiles

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