Suction anchor foundations serve as a critical anchoring solution for submerged floating tunnel (SFT) cable systems. In marine environments, these foundations must endure not only static loads but also long-term oblique cyclic loading caused by wave excitation, which can result in soil weakening and a reduction in bearing capacity. This study systematically examines the oblique cyclic bearing behavior of SFT suction anchors using a combined experimental and numerical approach. The results demonstrate that (1) the cyclic load ratio initially increases with increasing wave periods, then decreases, before rising again; (2) displacement accumulation at the mooring point occurs rapidly during the initial wave loading cycles, gradually stabilizing as cycling progresses; (3) during foundation failure, tension redistribution displays asymmetric characteristics, with connected cables experiencing load reduction while adjacent cables are subjected to amplified forces; (4) numerical analyses quantify key parametric relationships, revealing that the weakening coefficient (alpha) decreases with increasing loading angle, exhibits a positive correlation with zeta b, and shows a negative correlation with zeta c. These findings advance the understanding of cyclic performance in SFT anchors and offer essential insights for SFT safety evaluations.

A novel model is put forward to characterize the seismic response excited by vertical P-waves in a transversely isotropic and layered nonlocal poroelastic seabed. The proposed model integrates nonlocal parameter, anisotropy, and stratification to accurately examine wave propagation behavior. The fundamental equations for the underlying seabed are formulated using Biot's poroelastodynamic theory and Eringen's nonlocal theory. The wave equation for the overlying water is expressed in terms of the velocity potential. General solutions in both the poroelastic seabed and water layer are derived by solving the involved ordinary differential equations. Employing the newly devised and unconditionally stable propagator matrix scheme, semi-analytical solutions are derived for the time-harmonic response in a layered poroelastic seabed subjected to vertical P-wave excitation within the frequency domain. The validity of the proposed solutions is confirmed through rigorous comparison with the previously established analytical solutions. The influence of key material properties of seabed on the velocities of P-waves and free-field response in the poroelastic seabed is estimated in detail, along with the freefield response in a nonhomogeneous poroelastic seabed.