Abstract Submerged floating tunnel (SFT) is a new type of cable-supported structure system for strait crossing. Once the local anchor-cable suddenly fails, it will inevitably cause evident vibration and internal force redistributions of the structure. In order to study the dynamic responses and mechanical behaviors of the SFT subjected to abrupt anchor-cable breakage, a model test is conducted by a set of sensors installed on SFT for cable force, tube displacement and strain measurements. The transient dynamic signals following cable failure are tested and analyzed. Dynamic amplification factor (DAF) and dynamic coefficient (DC) are respectively used to evaluate the impact effect from the cable failure. Meanwhile, finite element simulations are also performed within ABAQUS. The establishments of the finished state of SFT before cable breakage and the dynamic cable failure process are presented both in the model test and FE model. Comparisons between the FE predicted values and the experimental results show a good agreement. On this basis, some influence factors are discussed in different cases of the cable-loss positions and the cable forces of ruptured cable, etc. The results show that the finished state of SFT under dead load (tube redundant buoyancy) after cable-force optimizations is more reasonable than that directly applying dead load without any cable-force adjustments, with more uniform cable force distribution and smaller tube deformation. Although the SFT suffers strong oscillations after sudden cable-breakage incident, no progressive collapse occurs when the safety margin of the rest structure is sufficient. The dynamic effect on remaining cable members due to sudden cable failure can be evaluated by DC method. A DC value of 1.5 is recommended to ensure the safety of SFT anchor-cables. When cable failure happens at the mid span of the tunnel, the deformation of SFT tube is most critical.

中文翻译：

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受局部锚索破坏的水下浮式隧道力学行为及试验研究

摘要 水下浮式隧道（SFT）是一种新型的跨海索支撑结构体系。一旦局部锚索突然失效，必然会引起结构明显的振动和内力重新分布。为了研究受到突然锚索断裂的 SFT 的动态响应和机械行为，通过安装在 SFT 上的一组传感器进行模型测试，用于测量索力、管位移和应变。测试和分析电缆故障后的瞬态动态信号。动态放大系数（DAF）和动态系数（DC）分别用于评估电缆故障的影响。同时，有限元模拟也在 ABAQUS 中进行。模型试验和有限元模型都给出了电缆断裂前SFT成品状态的建立和动态电缆破坏过程。有限元预测值与实验结果之间的比较显示出良好的一致性。在此基础上，讨论了不同工况下的索损位置、断裂索力等影响因素。 结果表明，索力优化后的静载（管冗余浮力）下的SFT成品状态比直接施加静载而不进行任何索力调整更合理，索力分布更均匀，管子变形更小。虽然在突然断线事件后 SFT 遭受了强烈的振荡，当其余结构的安全裕度足够时，不会发生连续倒塌。由于电缆突然故障对剩余电缆成员的动态影响可以通过直流方法进行评估。建议使用 1.5 的 DC 值以确保 SFT 锚固电缆的安全。当隧道中跨发生拉索故障时，SFT管的变形最为关键。