海上风机裙式斜壁桶形基础承载力及地基变形机理研究

Although bucket foundation has been gradually used in offshore wind turbines engineering, the research on bearing capacity and deformation mechanism of bucket foundation is still in its infancy, which can not meet the needs of engineering design, especially the new structure style of bucket foundation has rarely been innovated.The technique and method to prevent eroding around bucket foundation should be developed, the experiments including moment and torsion should be carried out, the bearing capacity and foundation failure theory of bucked foundation should be established. Therefore, a new structure-skirted and tapered bucket foundation for offshore wind turbines is to be studied in this project, with indoor test, numerical simulation and theoretical analysis.Firstly, the bearing capacity, deformation mechanism and failure model of skirted and tapered bucket foundation would be studied by tests with vertical load, horizontal load, moment and torsion. Secondly, the calculation method of bearing capacity of skirted and tapered bucket foundation would be found through the results of test, and the deformation mechanism and failure model would be discussed. Thirdly, the failure envelope and deformation law of skirted and tapered bucket foundation would be established, based on lots of changeable parameters comparatively simulation by verified and mature finite element method. This research would establish the basic theory for designing skirted and tapered bucket foundation, and would promote the application of bucket foundation in the offshore engineering.

虽然桶形基础已逐步应用至海上风电工程中，但是对其承载特性及变形机理的研究尚处于起步阶段，特别是对新型桶形基础结构形式的研究较少。当前有待发展防止桶形基础受冲刷失稳的技术与方法，有待针对桶形基础开展包括弯矩与扭矩荷载在内的试验研究，有待建立桶形基础承载性能与地基失稳理论。为此，本项目以新型结构-裙式斜壁桶形基础为研究对象，采取室内试验、数值模拟与理论分析相结合的研究手段。首先，对竖向荷载、水平荷载、弯矩、扭矩等单独作用及组合作用下裙式斜壁桶形基础的承载特性、变形机理与破坏模式进行试验考察；其次，通过归纳试验数据，建立各类荷载作用下裙式斜壁桶形基础承载力的经验计算公式，并探讨相应变形机理与破坏模式；再次，基于校验过的数值计算方法，通过大量变动参数比较研究，系统考察裙式斜壁桶形基础的变形特性，建立相应破坏包络面函数式。研究成果为裙式斜壁桶形基础的设计奠定理论基础，势必促进桶形基础的应用与发展。

斜壁桶形基础是海上风机工程中的新型基础形式，本项研究考察斜壁桶形基础的承载特性，得到了斜壁桶形基础分别受到竖向受压荷载、水平荷载与竖向受拉荷载时，土体沉降与极限承载力的变化规律，探讨了斜壁倾角与各极限承载力之间的定量关系；并创新性的提出了分段斜壁桶形基础，基于极限平衡法对分段斜壁桶形基础的水平承载力进行了系统性研究，提出了水平承载力计算方法，并进一步考察了斜壁倾角、桶高、桶径、土性参数等对水平承载力的影响；考察了系泊点位置与桶形基础吸力锚水平承载力之间的定量关系，得到了桶形基础吸力锚的各类破坏状态，分析了相应土体的变形与土压力分布情况。在本项目执行过程中，触类旁通地对网箱锚泊基础进行了探讨，创新性的提出了多种新型网箱锚泊基础，并申请系列专利。..本项目研究成果为斜壁桶形基础的设计奠定理论基础，势必促进桶形基础的应用与发展。在本项目执行过程中，为了能实现对桶形基础的竖向荷载、水平荷载、扭矩的同时加载，特设计加工了一套匹配科研设备，该设备具有开放性，后续将结合该设备进一步开展相关科研工作，拓宽该设备的使用范围，局部改造与提升其附加功能，开展更多的试验研究。创新性的提出了多种新型网箱锚泊基础并申请系列发明专利，这些所提设计方案具有标准化、部件化、模块化、系列化特性，为提高网箱锚泊基础的锚泊力与稳定性提供了新思路，为海水网箱养殖产业的健康发展提供技术支撑，具有重要的学术意义与工程实用价值。..项目资助发表论文5篇(其中EI收入3篇)，授权实用新型专利13项，申请发明专利25项，培养硕士生3名，锻炼10名以上本科生参与创新科技活动。今后将根据执行该课题过程中产生的衍生科学问题继续开展后续研究活动。