【作者】 刘喜珠；

【导师】 练继建；

【作者基本信息】 天津大学 ， 水利水电工程， 2010， 博士

【摘要】 发展可再生能源是全球趋势。由于海上风能资源丰富,而且不占用陆上耕地,远离居住区,噪音污染小,使其成为各国竞相开发的资源。但是由于海底地质条件难于勘测,海水中海流、波浪、海冰等环境荷载变化复杂,导致海上风力发电的基础结构施工建设困难、成本高,同时运行维护费用较高。如何降低成本且施工方便,成为基础结构设计的关键技术难题。在各项海上环境荷载作用下,如何保证海上风电基础结构的安全性,也是基础结构应用的必须解决的难点。针对我国海上风电发展阶段的需要,近海和滩涂风场的水深较浅,以往海洋桩基平台的大型打桩施工设备难以进入,本文考虑筒型基础施工速度快,便于在海上恶劣天气的间隙施工,可重复利用的特点,同时考虑到基础压载稳定和水面处抗冲刷的需要,将其与重力式基础结合,提出了海上风电大直径宽浅筒型基础结构的思想。海上风电基础结构承受大弯矩荷载,适用于近海和滩涂的筒型基础结构直径较大,筒基直径是以往任何工程都达不到的。本文对该种结构进行了较全面的研究,分为以下三个方面分析:(1)提出了一套适用于近海和滩涂的海上风电大直径宽浅筒型基础结构设计计算方法,给出了筒型基础筒壁承载式和筒顶承载式的两种承载力简化计算和结构设计模式,并对饱和粉砂地基中大直径宽浅筒型基础结构的破坏模式进行研究,采用有限元法对三维筒型基础模型进行承载力计算,验证了理论简化计算的可行性。(2)以筒型基础的重量为目标,将优化方法SQP和改进遗传算法首次应用于筒型基础的结构整体尺寸优化设计。在满足基础结构强度、刚度和稳定性的条件下,引入形状优化和拓扑优化,并采用有限元法对大直径筒型基础的传力体系进行局部优化设计。(3)基于流固耦合、固土耦合和非线性接触理论,建立筒土模型,筒土——塔架——简化机头整体模型。将有限元——离散元ALE计算方法,应用于大直径筒型基础结构的极限静荷载和风、波浪、海流随机荷载下的耦合动力安全性分析,全面反映筒型基础的受力机理和工作状态。同时,系统评估了海上风电筒型基础的安全性。更多还原

【Abstract】 Development of renewable energy is a trend in the world. Offshore wind resource has lots of advantage, such as rich, no occupating cultivated land, away from residences, little noise. All countries compete to develop it. But it is difficult to survey the geological conditions of seabed. Sea currents, waves, sea ice, ie, environmental loads are complex. That makes it difficult to construct infrastructure of offshore wind power, and high cost, high maintenance costs. How to reduce the cost and construct conveniently? This becomes the key technology of foundation design for offshore wind power. It is also the main problem and difficult to ensure offshore wind power foundation security in all kinds of environmental loads. In view of the development stage of offshore wind power in our country, it is planning to construct coastal and shallow beach wind power. Previous large-scale piling pile equipment for marine platform construction is difficult to access. This paper considers that the bucket foundation is constructed fast, reusable and easy to be constructed at the gap of bad weather. Taking the seabed foundation need of ballast stability and anti-erosion into account, the paper combines bucket foundation with gravity foundation, raising large-diameter and wide-shallow bucket foundation. With the great moment for the offshore wind power infrastructure, it is larger diameter used in coast and beach than previous any bucket foundation. This structure is comprehensively researched in the paper. The study field is divided into the three aspects as follows:(1) Proposing a system calculation method for large-diameter and wide-shallow bucket foundation using in coast and beaches. Presenting two types of simplified calculation of bucket foundation capacity and structural design pattern -- bucket foundation with its wall bearing and bucket foundation with its top bearing for the first time. Studying fuilare mode of large-diameter wide-shallow bucket foundation in saturated sand and bearing capacity of three-dimensional model with the finite element method to verify the feasibility of theoretical simplified calculation.(2) The SQP optimization method and the improved genetic algorithm are applied to the overall size optimization of bucket foundation design, with the goal of capacity safety factor for the first time. To meet the need of foundation strength, stiffness and stability, the shape optimization and topology optimization with the finite element method are used to local optimization of the large-diameter bucket foundation transmission system design for the first time, saving a huge amount of investment in project.(3) Based on fluid-soild coupling, solid-soil coupling and nonlinear contact theory, the soil-bucket foundation-tower-simplified wind generator model is built. The first time finite element- discrete element ALE method is applied to analysis security of large-diameter and wide-shallow bucket foundation with limit static load and random wind, waves, currents of the coupled dynamic load, fully reflecting the force mechanism and working condition of bucket foundation. Meanwhile, the paper establishs security assessment system for offshore wind power bucket foundation.更多还原