海上风机桶形基础安装与支撑结构动力特性研究

发布时间：2018-01-16 19:17

本文关键词：海上风机桶形基础安装与支撑结构动力特性研究　出处：《浙江大学》2014年博士论文　论文类型：学位论文

【摘要】：海上风能是一种安全、清洁、稳定的可再生能源,是缓解当前能源短缺、解决环境污染问题的战略选择。我国具有漫长的海岸线,海上风能储量大,开发前景好。随着风能开发从陆上走向海洋并逐渐向深海发展,特殊而恶劣的海洋环境对风机基础和整体结构的施工和运行提出了更高的要求。因此,海上风机建造的技术难度和经济成本也将显著提高,并成为制约其快速发展的瓶颈。吸力式桶形基础(简称吸力桶或桶形基础),因其具有安装简便、抗倾覆承载力高、节约材料、可重复利用等优点而将逐渐成为今后海上风机基础形式之一。而海上风机支撑结构,因其高且柔的结构特点和质量与刚度的分布规律,决定了它是一种自身动力特性受环境荷载、基础刚度等因素影响异常敏感的结构物。桶形基础的吸力安装和海上风机支撑结构动力特性研究涉及到海洋工程和岩土工程的交叉领域,许多问题是在当前国内大力发展海上风电背景下亟待解决的关键技术难题,具有重要的科学研究意义和工程应用价值。因此,本文针对这些问题,分别从理论分析、数值模拟和模型试验等方面进行了系统的研究和探索,具体工作主要包括以下几方面的内容： 1.利用室内桶形基础安装模型试验平台,开展了一系列粉土中吸力桶负压安装的模型试验,结合桶体端部和桶内土体中水力梯度变化趋势,系统分析了桶内吸力所引起的渗流对桶体沉贯阻力和土塞稳定性的影响；针对试验中观察到的土塞失稳现象并结合其失稳机理,提出了吸力安装中引入由土工织物和砾石组成的反滤装置改善桶形基础的吸力安装质量,并通过试验结果评估了该反滤装置的适用性,进而给出了相应的工程应用的建议。 2.基于考虑底部耦合刚度影响的风机结构整体模型,系统研究了水平刚度、转动刚度、耦合刚度和顶部竖向轴压力等参数对支撑结构前四阶自振频率的影响；并引入了考虑底端弹性约束的风机支撑结构自振频率近似计算理论；针对实际风机塔架“底部直径大、顶部直径小”的体型结构特点,研究了风机支撑结构动力特性中“锥化效应”影响；通过具体工程实例及本文模型试验结果验证了改进后的解析计算理论和近似计算方法的可靠性,并就相关参数对计算结果的敏感性做了分析。 3.基于无量纲化的相似性理论,在风机动力特性模型试验平台上,利用改进的循环加载装置,系统研究了由单桩支撑的结构模型,在不同特性循环荷载下的支撑结构自振频率和系统阻尼的变化规律；利用简化的数学计算模型,并结合土体的微观力学行为特性,解释了试验中所观察到的支撑结构自振频率变化规律；在此模型试验平台上还研究了由重力式浅基础、不同长径比的吸力桶基础、对称与非对称三脚架结构及四脚导管架等“多足”基础所支撑的模型结构动力特性及在循环荷载下动力特性变化规律；并基于试验结果给出了实际工程中有关风机基础选型及支撑结构设计上的相关建议。
[Abstract]:The sea wind is a safe, clean, stable and renewable energy, is to alleviate the energy shortage, the strategic choice to solve the problem of environmental pollution. China has a long coastline, offshore wind energy reserves, good development prospects. With the wind energy development from land to ocean, and gradually to the deep development, put forward higher the special requirements and the harsh marine environment construction and operation of the fan base and the overall structure. Therefore, the cost of technology and economy of offshore wind turbine construction will also be significantly improved, and become a bottleneck restricting its rapid development. The suction bucket foundation (referred to as the suction bucket or bucket Foundation), because of its easy installation, anti overturning and bearing capacity, material saving, using repeatedly etc and will become one of the offshore wind turbine foundation in the future. While the offshore wind turbine support structure, because of its high and soft structure and quality and stiffness The distribution rule determines that it is an abnormal sensitive structure which is influenced by environmental loads, basic stiffness and other factors.
Study on the dynamic characteristics of the structure involved in the field of marine engineering and geotechnical engineering support and installation of suction bucket foundation for offshore wind turbines, a lot of problems is a key technical problem to be solved urgently in the current domestic development of offshore wind power under the background, has important scientific significance and engineering application value. Therefore, this paper focuses on these the problem, from the theoretical analysis, the research and exploration of the system of numerical simulation and model test, the main work includes the following aspects:
1. using the model test platform for indoor installation of bucket foundation, model tests were carried out in a series of negative pressure suction bucket installed in silt, according to the change trend of hydraulic gradient barrel end and the barrel in the soil, analyzed the influence of seepage caused by the barrel suction penetration resistance and stability of soil plug barrel; according to the observed soil instability and the instability mechanism, put forward the suction filtration device of suction installation introduced by geotextile and gravel composition improvement of bucket foundation installation quality, and applicability of the filter device was evaluated by the test results, and the corresponding engineering application the suggestions are given.
2. based on the overall model of fan structure considering the effect of bottom coupling stiffness and horizontal stiffness system, rotational stiffness coupling, vertical stiffness and the top shaft pressure parameters on the supporting structure of four natural frequencies; and considering the bottom end of the elastic constraint fan support structure vibration approximation the frequency calculation theory; according to the actual wind turbine tower bottom diameter, top shape structure characteristics of small diameter ", on the fan supporting structure dynamic characteristics of" taper effect "; reliability analysis, the improved calculation theory and approximate calculation method is verified by engineering examples and the model test results, and the relevant parameters on the results of the sensitivity analysis is made.
3. based on similarity theory of dimension in the model test platform of wind power characteristics, cyclic loading device the improved system was investigated by single pile support structure model, change law of supporting structure in different characteristics under cyclic loading frequency and the damping of the system; using a simplified mathematical model and, combined with the microscopic mechanical behavior of soil, explained the support structure observed in the test of natural frequency changes; this model test platform is also studied by gravity shallow foundation, different length diameter ratio of the suction bucket foundation, dynamic characteristics of the model structure is supported by a symmetric and asymmetric structure and three tripod legs jacket "multiped" foundation and under the cyclic load dynamic characteristics; and based on the test results are given in the actual project on the foundation of fan selection and design of the supporting structure Relevant suggestions.

【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU476;TM315

【参考文献】