Abstract
In this study, a semi-analytical solution to the dynamic responses of a multilayered transversely isotropic poroelastic seabed under combined wave and current loadings is proposed based on the dynamic stiffness matrix method. This solution is first analytically validated with a single-layered and a two-layered isotropic seabed and then verified against previous experimental results. After that, parametric studies are carried out to probe the effects of the soil’s anisotropic characteristics and the effects of ocean waves and currents on the dynamic responses and the maximum liquefaction depth. The results show that the dynamic responses of a transversely isotropic seabed are more sensitive to the ratio of the soil’s vertical Young’s modulus to horizontal Young’s modulus (Ev/Eh) and the ratio of the vertical shear modulus to Ev (Gv/Ev) than to the vertical-to-horizontal ratio of the permeability coefficient (Kv/Kh). A lower degree of quasi-saturation, higher porosity, a shorter wave period, and a following current all result in a greater maximum liquefaction depth. Moreover, it is revealed that the maximum liquefaction depth of a transversely isotropic seabed would be underestimated under the isotropic assumption. Furthermore, unlike the behavior of an isotropic seabed, the transversely isotropic seabed tends to liquefy when fully saturated in nonlinear waves. This result supplements and reinforces the conclusions determined in previous studies. This work affirms that it is necessary for offshore engineering to consider the transversely isotropic characteristics of the seabed for bottom-fixed and subsea offshore structures.
Highlights
With the rapid development of technologies, marine resources are being exploited on a large scale
As waves and/or currents propagate in seawater, a time-varying wave pressure will be generated on the surface of the seabed, increasing the excess pore water pressure and decreasing the effective stress of the soil skeleton
It is necessary to study the dynamic responses of the seabed under wave and/or current loading
Summary
With the rapid development of technologies, marine resources are being exploited on a large scale. Ye and Jeng [30] initiated the analysis of the dynamic responses of a single-layered isotropic poroelastic seabed under wave and current loadings in two dimensions based on the PD model and discussed the transient liquefaction depth of the seabed, respectively, under a following current and an opposing current. Their conclusions indicated that the current’s influence on the pore pressure should not be neglected, and the maximum liquefaction depth increases under the following current while decreasing under the opposing current. Maximum liquefaction depths of the single-layered TIP and the multilayered TIP seabed
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
