近海风机吸力式桶形基础基于变形控制的复合承载力研究

发布时间：2018-06-09 05:37

本文选题：吸力桶 + 近海风机　；参考：《浙江大学》2013年硕士论文

【摘要】：风能作为重要和最成熟的可再生能源,是全球能源发展战略的重要方向。中国具有丰富的近海风能资源,大力发展海上风电具有重要意义。作为风机上部荷载的最终承担者,地基基础是风电机组设计的重要内容。吸力式桶形基础因其造价低、施工方便等优点,显示出可观的工程应用前景。针对国内逐渐增多的建设于粉土、砂土海床地基的近海风机,本文通过大比例1g模型试验获得了粉土中吸力式桶形基础变形及受力特性。考虑风机基础正常运行时须严格控制其转动角,研究了吸力桶基于变形控制的承载力分析方法。通过在砂质粉土中开展的一系列不同尺寸的单桶基础倾覆加载模型试验,研究其在竖向力、水平力和弯矩荷载共同作用下的变形机制和承载性能,试验结果揭示了桶直径、高宽比和加载偏心比对桶基无量纲弯矩承载力的影响,以及不同桶基转动中心位置。基于桶基变形和桶土相互作用机理,提出了新的基于变形控制的复合承载力分析方法,并讨论了计算参数的确定方法。该分析方法可对粉土中模型试验和砂土中现场试验的弯矩-转角曲线进行较好的预测,使任意允许转角对应的承载力计算成为可能。进一步的研究表明,被动区桶裙外壁上土压力和桶土摩阻力对桶基弯矩承载力贡献最大,具体桶基高宽比和水平地基抗力常数对弯矩承载力影响最大。针对多桶基础,本文重点考虑其抵抗风浪荷载时上拔桶的作用。通过系列不同尺寸的单桶基础上拔加载模型试验,研究了不同加载速率对上拔承载力的影响以及桶内负压的作用,以及土体对桶体上拔的响应。在此基础上对多桶基础进行了水平静力和循环加载模型试验,利用三自由度力传感器获得各桶真实受荷情况。通过试验讨论了多桶基础极限倾覆承载力分析方法,研究了多桶基础在不同荷载水平下的循环累积变形以及各桶的受力发展。
[Abstract]:As an important and most mature renewable energy, wind energy is an important direction of global energy development strategy. China has abundant offshore wind energy resources, and it is of great significance to develop offshore wind power. As the ultimate bearer of wind turbine upper load, foundation is an important part of wind turbine design. Suction bucket foundation has the advantages of low cost and convenient construction. In this paper, the deformation and mechanical characteristics of suction bucket foundation in silty soil are obtained by large scale 1 g model test in view of the increasing offshore fan built on silt and sand seabed foundation in China. Considering the need to strictly control the rotation angle of fan foundation in normal operation, the bearing capacity analysis method of suction bucket based on deformation control is studied. A series of model tests on overturning load of single bucket foundation with different sizes are carried out in sandy silty soil. The deformation mechanism and bearing capacity of the bucket under the combined action of vertical force, horizontal force and moment load are studied. The experimental results reveal the influence of bucket diameter, aspect ratio and loading eccentricity ratio on the dimensionless moment bearing capacity of bucket foundation. And different barrel base rotation center position. Based on the mechanism of bucket foundation deformation and bucket soil interaction, a new composite bearing capacity analysis method based on deformation control is proposed, and the determination method of calculation parameters is discussed. This method can be used to predict the bending moment-angle curves of model tests in silty soil and field tests in sand, which makes it possible to calculate the bearing capacity corresponding to any allowable rotation angle. Further study shows that the earth pressure and soil friction on the outer wall of the bucket skirt in the passive zone contribute most to the bending moment bearing capacity of the bucket foundation, and the ratio of height to width of the bucket foundation and the resistance constant of the horizontal foundation have the greatest influence on the moment bearing capacity of the bucket foundation. This paper focuses on the role of bucket pullout when it is used to resist wind and wave loads. The effects of different loading rates on the uplift bearing capacity, the negative pressure in the bucket and the response of the soil to the uplift of the bucket were studied through a series of model tests of pull-out on a single bucket foundation with different dimensions. On this basis, the horizontal static and cyclic loading model tests of multi-bucket foundation are carried out, and the real loading conditions of each bucket are obtained by using the three-degree-of-freedom force sensor. The ultimate overturning bearing capacity analysis method of multi-bucket foundation is discussed through experiments. The cyclic cumulative deformation of multi-bucket foundation under different load levels and the development of each bucket are studied.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU473.1

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