筒型基础水平向和抗倾承载力的极限分析上限解

Upper bound limit analysis of horizontal and moment ultimate bearing capacities of bucket foundation

海上风电是我国近年来重点发展的能源形式之一,大直径宽浅式筒型基础作为一种新型海上风电基础,具有更好的抗倾覆承载能力,更加适用于我国近海软黏土较多的土质特点;并可以实现岸边预制、海上基础-塔筒-风机整体浮运与安装,具有良好的经济效益。为更好地掌握宽浅式筒型基础的承载特性,针对海上风电基础承受水平向与倾覆荷载较大的特点,开展了数值分析对筒型基础的单向极限承载性能进行研究,得到水平向以及抗倾极限承载力和对应的承载模式;并基于筒型基础的承载模式,建立相应的破坏机动场和速度场,结合虚功方程和内部能量损耗率函数,采用数学软件编程求解了宽浅式筒型基础水平向和抗倾承载力的极限分析上限解,计算结果与数值结果的吻合程度良好。

Offshore wind energy is one of the most important clean energy sources developing in China in recent years. As a new type of offshore wind turbine foundation, the wide-shallow bucket foundation with large diameter has a good ability to withstand moments.It is thus suitable for offshore region in China with soft clay deposits. Moreover, this type of foundation has advantages of onshore prefabrication, foundation-tower-turbine integrated floating transportation and suction installation, resulting in a good benefit for cost reduction. To better understand the bearing capacity of the wide-shallow bucket foundation in clay, numerical analyses are conducted to study the monotonic ultimate bearing behavior. The horizontal and moment ultimate bearing capacities and corresponding failure mechanisms are obtained. By building the velocity field based on the failure mechanisms of the bucket foundations, combined with the virtual work equation and the internal energy loss rate function, the upper bound solutions for the horizontal and moment ultimate bearing capacities of the bucket foundations are established and programmed using mathematical software. The results of the upper bound limit analysis have a good agreement with the calculation of the numerical analysis.