离岸深水全直桩码头结构长期承受波浪力、撞击力等动荷载作用,仅从静力角度分析不能满足工程设计要求。为研究离岸深水全直桩码头结构动力简化计算方法,利用ABAQUS软件建立了全直桩码头的嵌固点模型和结构-地基相互作用的三维弹塑性有限元模型。基于所建立的有限元模型,采用模态分析法研究了上述码头结构的自振特性。分析表明,结构基本周期较长,与波浪力、撞击力荷载周期接近,结构动力响应突出。进一步计算发现,全直桩码头结构在波浪力、撞击力荷载作用下的动力响应有限元计算结果与采用单自由度系统位移动力放大系数理论公式计算结果吻合较好,由此提出全直桩码头结构动力响应可按单自由度系统位移动力放大系数理论公式进行简化计算。在此基础上,结合规范中的m法、p-y曲线法、NL法提出了上述码头结构动力简化计算方法,通过与动力有限元计算结果对比,验证了所建立简化计算方法的正确性。
All-vertical-piled wharf in offshore deep-water subjects to dynamic load for a long time, such as wave load and impact load, only static analysis cannot meet the requirement of the engineering design. In order to research dynamic simplified calculation method of all-vertical-piled wharf in offshore deep-water, an embedded solid finite element model and the structure and soil interaction 3D elastoplastic finite element model are established by using ABAQUS software. Based on the established finite element model, the natural vibration characteristics of above-mentioned wharf are studied by employing modal analysis method. The analysis indicates that fundamental period of structure is relatively long, and it is close to periods of wave load and impact load;so dynamic response of structure is remarkable. Then the further calculations have shown that the results of dynamic finite element and the theory formula of the dynamic amplification coefficient of single-degree-of-freedom system under wave load and impact load are in good agreement;so dynamic response simplified calculation method of the wharf is put forward. On this basis, the dynamic simplified calculation method is proposed combining with m method, p-y curves method and NL method. In comparison with the dynamic finite element method, the dynamic simplified calculation method is reliable.