# Numerical Simulation of a Submerged Floating Tunnel: Validation and Analysis
## 5 Conclusions  
Few scholars have employed the CEL method to numerically simulate the dynamic response of SFTs. In this study, two simulated examples were explored to demonstrate the reliability of the CEL method for calculating both one-way and two-way fluid-structure coupling problems. Based on this, a CEL numerical model of an SFT was established, \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
\begin{tabular}{c} **Seismic Wave** \\ **Acceleration** \\ **(\(\times\)\(g\))** \\ \end{tabular} & \multicolumn{2}{c}{**Cable Force (MPa)**} & \multicolumn{2}{c}{**Horizontal Hydrodynamic Load (Pa)**} & \multicolumn{2}{c}{**Horizontal Acceleration of the Tube (m/s\({}^{2}\))**} \\ \cline{2-7}  & \(\sigma_{m}\) & \(\sigma_{p}\) & \(P_{m}\) & \(P_{p}\) & \(a_{p}\) & \(a_{m}\) \\ \hline
0.01 & 3.40 & 169.85 & 11 & 550 & 0.11 & 0.11 \\
0.03 & 10.70 & 535.03 & 30.5 & 1525 & 0.41 & 0.41 \\
0.05 & 83.51 & 4175.51 & 202 & 10,100 & 3.68 & 3.68 \\
0.07 & 135.20 & 6760.08 & 322.8 & 16,140 & 5.98 & 5.98 \\
0.09 & 152.92 & 7646.14 & 369.2 & 18,460 & 6.57 & 6.57 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Peak values of the dynamic response indices of the prototype and model under various seismic wave intensities. and its results agree well with those of previously published shaking table experiments, indicating that the CEL method can effectively simulate the dynamic response of SFTs under seismic effects. Finally, the dynamic response of an SFT under an earthquake was analyzed, and the following conclusions were drawn. 1. The verification of the CEL method in two hypothetical cylindrical flow calculations and a comparison of the results with those of experimental model SFT tests demonstrated that the CEL method is capable of effectively simulating the seismic dynamic response of SFTs. 2. The natural frequency of an SFT prototype in a water environment was found to be 1.5 Hz. Thus, when conducting the seismic design of the SFT, the response of the structure under earthquake action should be evaluated. In the analysis, it is necessary to consider the matching relationship between the natural frequency of the structure and the frequency of the earthquake wave motion in order to determine the resonance condition of the structure and its corresponding seismic response characteristics. 3. The seismic warning threshold for the prototype SFT was 0.03\(\times\)\(g\). Thus, if an SFT based on this prototype is applied in a real-life setting, an earthquake early warning alarm would need to be issued once the ground motion acceleration reached this level. This would ensure that the anchor cable had a sufficient level of safety redundancy, and it would allow the operating company ample time to implement earthquake response measures. 4. Under seismic conditions, the peak acceleration of the prototype SFT tube body significantly increased, leading to amplification effects. Therefore, in the seismic design of SFTs, the interaction between the tube body, anchor cable, and seabed should be the foremost consideration. Overall, our findings reveal that the CEL method's potential applications in fluid-structure interaction analysis transcend traditional boundaries, demonstrating its remarkable adaptability in simulating the responses of intricate underwater structures under seismic conditions. This discovery not only expands the realm of CEL method applications, but also introduces a novel and promising numerical simulation approach for seismic research on submerged floating tunnels. However, it is worth emphasizing that our research results are preliminary and require further investigation and improvements. While the successful application of the CEL method in simulating seismic responses of submerged floating tunnels provides robust initial support for its reliability and effectiveness in engineering applications, further refinement and validation are crucial to ensure its widespread adoption and optimal performance.