【作者】 吕娜；

【导师】 练继建；

【作者基本信息】 天津大学 ， 水利水电工程， 2010， 硕士

【摘要】 海上风能是一种丰富的清洁可再生能源,但是海上风力发电机的基础结构所处的环境复杂,导致运输施工困难、造价成本高,另外如何保证海上风机基础结构在复杂的荷载作用下的稳定和安全性,也是当今研究的热点。筒型基础作为一种新型的海上的平台基础,具有施工简便,机动灵活,使用安全可靠,可实现回收复用等特点,被广泛应用于各种海上结构设施。本文利用筒型基础的这些特点,设计了新型的海上风机筒型基础,并通过理论分析和数值模拟,对这种形式的海上风机基础运用于实际工程的可行性进行了研究,重点研究如下几个问题:(1)根据所选择的风机场址,确定风电场特定的外部条件。分析海上风机筒型基础在使用过程中受到的各种荷载,并给出相应的理论计算方法,确定筒型风机基础计算工况。分析筒型基础的特点和工作机理,阐述筒型基础承载特性的理论计算方法。介绍了筒型基础充气浮运的浮稳性的理论分析方法,通过稳性高参数来判断气浮体的浮稳性。介绍影响筒型基础负压沉贯的几个因数,并给出计算负压值的理论公式,用于指导平台就位施工时的负压控制。(2)根据前面介绍的筒型基础设计要点,提出了适用于浅海的钢结构形式和钢混组合形式两种筒型基础方案,并对两种方案从基础重量、造价、稳定性、施工阶段的拖航浮运沉贯几个方面进行了比较,选出了较优的方案钢混组合基础。(3)通过有限元分析软件ABAQUS,对较优方案钢混组合筒型基础进行了数值分析计算。校核基础在正常运行工况下和极限工况下,位移和应力,并具体分析了土体对筒基的作用。采用位移控制法对筒型基础在单向荷载作用下地基的承载特性进行了数值计算和分析,为复合加载模式下海上风机筒型基础的承载特性分析奠定了基础。(4)选取了适当的疲劳S-N曲线,并结合有限元分析,评价了基础钢结构的疲劳寿命,为基础的设计提供依据。更多还原

【Abstract】 Maritime wind energy is an abundant, clean and renewable energy, but the Infrastructure for offshore wind turbine in which the environment is so complex that it is difficult to transport construction, and the construction cost high; in addition, how to ensure the stability and security of the offshore wind turbine infrastructure under complex loads is a hot project today. As a new-style platform foundation, bucket foundation is widely used in various marine structures facilities for the reasons that it has so many merit such as simple structure, flexible, reliable and reusable. In this paper, a new-style offshore bucket foundation was designed, and its feasibility was studied through theoretical analysis and numerical simulation. Focusing on the following issues:(1) According to the fan site choiced, the specific farms external conditions are determined. Various loads will focus on the bucket foundation during use. The loads were analyzed and the corresponding theoretical calculating methods of these loads are gived in the paper to determine work condition. Analysed the characteristics of bucket foundation and working mechanism to explain the theoretical calculating methods of bucket foundation’s load-bearing characteristics. The theoretical analysis of the static stability of air float bucket foundation was introduced. Whether an air float structure is in stability can be judged by the parameter of stabilizing height. Several factors that effects suction penetration of bucket foundation were introduced, and the theoretically calculating formula of underpressure was provided. Allowable value of negative pressure changed with the inserting depth of bucket foundation. The transformation was obtained to used to guide the underpressure-control during construction period.(2) According to the basic design elements, Steel structure and Steel-concrete Composite Fucket Foundation are designed. And coMPared two programs from basic weight, cost, stability, the towing floating and suction penetration during construction, and then the steel-concrete combination program was chosen as the best one.(3) The bucket foundation that designed were numerically calculated and analyzed in ABAQUS. Checked the displacement and stress under normal operating conditions and extreme conditions, and specifically analysed the influence that acted on the bucket foundation by soil. The bucket foundation’s load-bearing characteristics under monodirectional loads were numerically calculated using displacement control method, then lay the foundation of the numerical calculation of the bucket foundation’s load-bearing characteristics under combined loading.(4) Evaluated the fatigue life of steel structures in the method of finite element analysis using the appropriate fatigue SN curves, to provide evidence-based theories for the design of foundation.更多还原