**7. Conclusions**

In this study, an integrated numerical model including a LRBFCM seabed model based on Biot "*u* − *p*" approximation is proposed to investigate the flow field dynamics and corresponding seabed behaviour around an immersed tunnel under second-order stokes wave combined current with various velocities. The oscillatory liquefaction under the different wave characteristics, soil properties, and current velocities are discussed in detail. From the numerical result, the following conclusions can be drawn:


**Author Contributions:** Conceptualization, D.-S.J.; methodology, C.-C.T. and S.H.; validation, S.H.; formal analysis, S.H.; writing—original draft preparation, S.H.; writing—review and editing, D.-S.J. and C.-C.T.; supervision, D.-S.J. and C.-C.T.

**Funding:** This research received funding from the Ministry of Science and Technology of Taiwan under the grant no. MOST 106-2918-I-022-001.

**Acknowledgments:** The first author is grateful for the support of High Performance Computing Cluster "Gowanda" to complete this research, and the supporting of scholarship from Griffith University. The third author is grateful for the support of the Ministry of Science and Technology of Taiwan under the grant no. MOST 106-2918-I-022-001.

**Conflicts of Interest:** The authors declare no conflict of interest.
