Abstract: The large-diameter single-pile foundation is the main form of offshore wind turbine. It is of great significance to evaluate the horizontal bearing capacity of the pile foundation and the 1st natural frequency of the wind turbine to optimize the design. The numerical analysis method of the strength degradation of soft clay based on non-linear kinematic hardening model was developed. The comparisons with triaxial tests and centrifuge test results showed that the method had reliabilities in analyzing the strength degradation of the soil and interaction of pile-soil system. The method analyzed the effects of cyclic loading on the stiffness of pile-soil system, the bearing capacity of pile foundation and the 1st natural frequency of the wind turbine. The results showed that the effect of cyclic load amplitude was greater than the number of cycles when the number of cycles was small. The bending stiffness and flexural bearing capacity of the pile-soil system were attenuated more than the horizontal stiffness and the lateral bearing capacity. Due to the limited degree of stiffness attenuation, the overall first-order natural frequency of the wind turbine was not significantly reduced.
刘润,黄旋智,袁宇,马鹏程. 土体弱化对海上风电单桩基础的影响研究[J]. 隧道与地下工程灾害防治, 2019, 1(4): 56-63.
LIU Run, HUANG Xuanzhi, YUAN Yu, MA Pengcheng. Study of soil degradation effects on offshore wind turbine with large-diameter pile foundation. Hazard Control in Tunnelling and Underground Engineering, 2019, 1(4): 56-63.
张陈蓉, 俞剑, 黄茂松. 软黏土中水平循环荷载作用下刚性短桩的p-y曲线分析[J]. 岩土工程学报, 2011, 33(增刊2): 78-82. ZHANG Chenrong, YU Jian, HUANG Maosong. P-y curve analyses of rigid short piles subjected to lateral cyclic load in soft clay[J]. Chinese Journal of Geotechnical Engineering, 2011, 33(Suppl.2): 78-82.
[2]
马明泊. 循环荷载下海上风电单桩基础水平承载性能退化研究[D].青岛:中国海洋大学,2015. MA Mingbo. Research on degradation of lateral bearing capacity for offshore wind turbine monopile under cyclic loading[D]. Qingdao: Ocean University of China, 2015.
[3]
RAJASHREE S S, SUNDARAVADIVELU R. De-gradation model for one-way cyclic lateral load on piles in soft clay[J]. Computers and Geotechnics, 1996, 19(4): 289-300.
[4]
黄茂松, 刘莹. 基于非线性运动硬化模型的饱和黏土桩基础竖向循环弱化数值分析[J]. 岩土工程学报, 2014, 36(12): 2170-2178. HUANG Maosong, LIU Ying. Numerical analysis of axial cyclic degradation of a single pile in saturated soft soil based on nonlinear kinematic hardening constitutive model[J]. Chinese Journal of Geotechnical Engineering, 2014, 36(12): 2170-2178.
[5]
POULOS H G. Cyclic axial response of single pile[J]. Journal of Geotechnical Engineering, 1981, 107(1): 41-58
[6]
张光建. 长期水平循环荷载下大直径桩的累积位移分析[D]. 杭州: 浙江大学, 2013. ZHANG Guangjian. Analysis on horizonal displacement of monopile foundations under long-term cyclic later loading[D]. Hangzhou: Zhejiang University, 2013.
[7]
ACHMUS M, KUO Y S, ABDEL-RAHMAN K. Behavior of monopile foundations under cyclic lateral load[J]. Computers and Geotechnics, 2009, 36(5): 725-735.
[8]
ANDERSEN L V, VAHDATIRAD M J, SICHANI M T, et al. Natural frequencies of wind turbines on monopile foundations in clayey soils: a probabilistic approach[J]. Computers and Geotechnics, 2012, 43: 1-11.
[9]
李益. 三桩基础海上风力发电结构的自振特性分析[D]. 大连: 大连理工大学, 2013. LI Yi. Natural vibration characteristic analysis of triple-piles based offshore wind power structure[D]. Dalian: Dalian University of Technology, 2013.
[10]
LOMBARDI D, BHATTACHARYA S, MUIR WOOD D. Dynamic soil—structure interaction of monopile supported wind turbines in cohesive soil[J]. Soil Dynamics and Earthquake Engineering, 2013, 49: 165-180.
[11]
封晓伟. 波浪循环荷载作用下防波堤—地基稳定性研究[D]. 天津: 天津大学, 2010. FENG Xiaowei. Researches on the breakwater-foundation stability under wave cyclic loading[D]. Tianjin: Tianjin University, 2010.
[12]
ZHANG C R, WHITE D, RANDOLPH M. Centrifuge modeling of the cyclic lateral response of a rigid pile in soft clay[J]. Journal of Geotechnical and Geoenvironmental Engineering, 2011, 137(7): 717-729.
[13]
SIVER M L, SEED H B. Deformation characteristics of sands under cyclic loading[J]. Journal of the Soils Mechanics and Foundations Division, ASCE, 1971, 97(8):1081-1098.
2019, Vol. 1 
