地震与随机波流激励下悬浮隧道及其锚索的耦合动力学分析

Submerged floating tunnel is an innovative crossing long and deep-strait transportation. The submerged floating tunnel and cable members are affected by various complicated environmental conditions, the coupling between submerged floating tunnel and its cables, and the dynamic coupling between those nonlinear factors. The submerged floating tunnel and cable members may experience complex nonlinear dynamics under those nonlinear conditions, which is key to structural safe operation. Based on the previous works of applicant, firstly, deficiencies of existed methods are analyzed, new and more reasonable calculation method for random wave force and vortex-induced lift force are proposed. Secondly, the effects of earthquake to the wave field and streaming potential are investigated by the Radiation wave theory and the revisionary Morison equation, a computational formula for dynamic water pressure induced by oceanic earthquake is proposed, and the calculation method for submerged floating tunnel and cables members under couple effects between earthquake and hydrodynamic force is established. Thirdly, the dynamic coupling effect between submerged floating tunnel and its cables is considered, and the dynamic analysis model for submerged floating tunnel and cable members under earthquake and random wave-current excitation is established. At last, the hydrodynamic calculation program based on present dynamic analysis model is build, the present method is validated by the existed methods and experimental data, and key parameters’ sensitivity analysis are applied to guide for engineering optimum design. The research has important theoretical and engineering application value for the design and construction of the mooring system of submerged floating tunnel.

悬浮隧道为创新型跨越长深水域交通结构物，在波流、地震、隧体与其锚索相互作用等因素耦合作用下，悬浮隧道及其锚索振动响应呈现复杂的非线性特征，成为关系结构安全运营关键难点问题。本项目在申请人前期工作基础上，首先，针对现有研究没有考虑波流随机性及流固耦合作用等不足之处，提出更合理的作用于悬浮隧道锚泊系统的随机波浪力及涡激力计算方法；然后，基于辐射波理论及修正Morison法，构造海洋地震动水压力计算公式，提出海洋地震发生时地震与随机波流耦合作用载荷的计算方法；进而，基于前述载荷激励计算方法，分析隧体与其锚索的耦合动力作用，建立地震与随机波流激励下悬浮隧道及其锚索的耦合动力学分析计算模型；最后，基于数学模型编制水动力计算分析程序，通过已有数值方法及物理模型试验进行模型验证，对影响结构安全稳定的关键参数进行敏感性分析，指导工程设计方案优化。研究成果可为悬浮隧道锚泊系统设计施工提供理论依据及技术支持。

悬浮隧道为创新型跨越长深水域交通结构物，在波流、地震、隧体与其锚索相互作用等因素耦合作用下，悬浮隧道及其锚索振动响应呈现复杂的非线性特征，成为关系结构安全运营关键难点问题。在申请人前期工作基础上，首先，针对现有研究没有考虑波流随机性及流固耦合作用等不足之处，利用线性波浪理论和随机相位谱法构造了随机波浪力时域激励，并建立了随机Morison公式计算流体阻力的方法，以Blevins和Burton提出的升力近似数学模型为基础，建立了动态涡激升力计算方法。然后，基于辐射波理论及修正Morison法，构造海洋地震动水压力计算公式，提出海洋地震发生时地震与随机波流耦合作用载荷的计算方法，结合有限单元法建立悬浮隧道锚索在水动力和地震共同作用下的数学分析模型。进而，利用波流水槽，结合特殊设计的载荷传递装置将小型地震振动台振动传递到水底，从而模拟水下地震和波流作用，通过试验手段进行地震与随机波流激励下悬浮隧道及其锚索的耦合动力学分析，并与前期开展的理论及数值研究进行对比验证。最后，基于数值模型及物理模型试验，对影响结构安全稳定的关键参数进行敏感性分析，指导工程设计方案优化。项目建立了考虑地震与波流耦合作用的悬浮隧道及其锚索的耦合振动的数值及试验模拟方法，极大提高了悬浮隧道抗震分析方法的准确性，研究成果可为悬浮隧道锚泊系统设计施工提供理论依据及技术支持。成果发表在《Ocean Engineering》、《Ships and Offshore Structures》等国内外高水平期刊，得到港珠澳大桥总工林鸣、英国Jeom Kee Paik院士等学者的高度认可。成果应用于南海某人工岛、广西南宁邕江沉管工程、广西百色右江沉管过程等多个重点工程的浮体锚泊系统设计及施工。