Abstract Roughly 90% of all natural vibrations have epicenters in offshore zones and may cause destruction of submarine and floating structures. Such excitations can influence the safe performance of facilities set up on the seabed, like tunnels, jacket legs and subsea oil pipelines. Some researches on this theme have been carried out to demonstrate the importance of seaquake analyses and their effects have been underlined. The present study intends to numerically simulate a two-dimensional fluid-structure interaction (FSI) problem in order to examine the dynamic response of submarine tunnel under real horizontal earthquakes. Pressure is considered as independent nodal variables to represent the fluid flow effects and the induced time-dependent acceleration in porous medium equation is incorporated in the analysis and the tunnel shell is considered as flexible. This work highlights the importance of the input ground motion frequency content that governs the development of the induced seismic stress/strain around the lining of the tunnel. The results demonstrate that for deep sea the increment rate of the circumferential stress caused by surface gravity waves is below 7% when compared to the no-wave interface condition. Moreover, it is confirmed that long-period record may amplify the overall response of the system (up to 60%) specially the lateral and vertical displacements, as well as the principal stress to a lesser extent. The developed numerical model can attend to further analysis of tunnels embedded in a half-space in conjunction with fluid undergoing the severe long-period earthquakes.

中文翻译：

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一种模拟地震频率含量对海底隧道地震行为影响的耦合数值方法

摘要 大约90%的自然振动震中在近海区域，可能导致海底和浮式结构的破坏。这种激励会影响海底设施的安全性能，如隧道、导管架腿和海底石油管道。已经针对这一主题进行了一些研究，以证明海震分析的重要性，并强调了它们的影响。本研究旨在对二维流固耦合 (FSI) 问题进行数值模拟，以检验海底隧道在真实水平地震下的动力响应。压力被认为是独立的节点变量来表示流体流动效应，多孔介质方程中的感应时间相关加速度被纳入分析，隧道壳被认为是柔性的。这项工作强调了输入地震动频率内容的重要性，这些内容控制隧道衬砌周围诱发地震应力/应变的发展。结果表明，与无波浪界面条件相比，深海表面重力波引起的周向应力增量小于7%。此外，证实长期记录可能会放大系统的整体响应（高达 60%），特别是横向和竖向位移，以及较小程度的主应力。