循环荷载作用下拖曳锚极限抗拔承载力分析

Analysis on ultimate pullout bearing capacity of drag embedment anchor under cyclic loading

摘要:

在海洋工程锚固基础设计中,为了研究拖曳锚在风、浪、流等循环荷载条件下的极限抗拔承载力性能,分别利用理想弹塑性模型和刚体模型模拟海床饱和软黏土地基和拖曳锚,考虑拖曳锚与海床土之间的接触摩擦,建立二维拖曳锚承载力有限元计算模型．在循环荷载作用下,将Andersen提出的循环强度模型概念引入,分别对埋置深度和荷载循环次数对拖曳锚循环极限抗拔力的影响规律进行研究．结果表明:埋深对循环极限抗拔力的影响相对较小一些;而随着荷载循环次数的增加,循环极限抗拔力则逐渐降低且趋于平缓．具体数值计算结果与分析结论可为工程设计提供参考依据．

Abstract:

During the design of anchor foundation of offshore structures, aiming at the investigation of the ultimate pullout bearing capacity analysis of drag embedment anchor under cyclic loads of wind, wave and current, the undrained seabed soft clay and drag embedment anchor are respectively simulated by ideal elastic-plastic model and rigid model. Considering the contact friction between the drag embedment anchor and seabed clay, the two-dimensional finite element calculation model is established. Under cyclic loading, concept of cyclic strength from Anderson is introduced, and then the influence laws of embedment depth and load cycle times to ultimate cyclic pullout bearing capacity of drag embedment anchor are respectively investigated. The results show that the embedment depth has little influence on cyclic ultimate pullout bearing capacity. With the load cycle times gradually increasing, the cyclic ultimate pullout bearing capacity of drag embedment anchor gradually decreases and the decreased degree gradually becomes small. The specific numerical results and analysis conclusions would be helpful in engineering practices.