摘要:
海上风力发电是国家风电能源战略的核心，吸力式筒型基础凭借其良好的承载性能、可回收利用及环境友好优势，有望成为海上风力发电构筑物主要的基础形式之一。以吸力筒为基础的深海浮式平台在较大的上拔速度作用下，基础破坏模式为整体剪切破坏，在该破坏模式下对吸力式筒型基础采取极限分析上限法研究，可在保证平台安全的前提下，合理且经济选用基础尺寸。本研究基于反向Meyerhof破坏机制，结合饱和海洋黏土的非均质特性，提出改进上限分析方法。通过引入不排水抗剪强度随深度的线性梯度效应，建立虚功平衡方程，推导出吸力筒基础整体剪切破坏下抗拔承载力上限解析解。与模型试验和部分传统理论进行对比，进而验证所推导的上拔承载力上限解公式的合理性和有效性，进一步通过参数敏感性研究，系统揭示筒体长径比等几何参数对承载力系数Nc的影响规律，结合承载力归一化处理明晰了各因素的影响效应。结果表明上限解F与各参数之间呈正相关；当通过只改变吸力筒半径或只改变吸力筒筒长改变长径比时，归一化承载力系数Nc随长径比变化呈现不同趋势。所推导出的解析理论公式相对于传统理论更接近于模型试验的结果，表明该上限解析式在误差允许范围内是合理的，具有一定的应用潜力。
Abstract:
Offshore wind power generation is the core of the national wind power energy strategy, and the suction cylinder foundation is expected to become one of the main foundation forms for offshore wind power generation structures by virtue of its good load-bearing performance, recyclability and environmentally friendly advantages. Under the action of large uplift velocity, the foundation damage mode of the deep-sea floating platform based on suction cylinder is overall shear damage, and the limit analysis upper limit method is adopted to study the suction cylinder foundation under this damage mode, which can reasonably and economically select the foundation size under the premise of ensuring the safety of the platform. In this study, based on the reverse Meyerhof damage mechanism, combined with the non-homogeneous characteristics of saturated marine clay, an improved upper limit analysis method is proposed. By introducing the linear gradient effect of undrained shear strength with depth and establishing the virtual work balance equation, the analytical solution of the upper limit of the pullout capacity under the overall shear damage of the suction cylinder foundation is deduced. Comparison is made with model tests and some traditional theories to verify the reasonableness and validity of the derived upper limit solution formula for the uplift bearing capacity, and further through the parameter sensitivity study, the influence of geometrical parameters such as the cylinder length-to-diameter ratio on the bearing capacity coefficient Nc is systematically revealed, and the influence effect of each factor is clarified by combining with the normalisation process of the bearing capacity. The results show that there is a positive correlation between the upper limit solution F and each parameter; when the length-diameter ratio is changed by changing only the radius of the suction cylinder or only the length of the suction cylinder, the normalised load carrying capacity coefficient Nc shows a different trend with the change of the length-diameter ratio. The derived analytical theoretical formulas are closer to the results of the model tests than the traditional theories, indicating that the upper limit analytical formulas are reasonable within the error tolerance and have certain potential for application.
百度学术
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