Seabed seismic analysis using exact responses of solid-liquid free field for 2D oblique incident waves by finite/infinite element method

• Published in: Ocean engineering Vol. 285; p. 115171
• Main Authors: Yang, Y.B., Zhou, Z.Y.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.10.2023
• Subjects: Equivalent seismic forces; Finite/infinite element method; Oblique incident seismic waves; Seabed seismic analysis; Solid-liquid coupling; Finite/infinite element method; Solid-liquid coupling; Seabed seismic analysis; Oblique incident seismic waves; Equivalent seismic forces
• ISSN: 0029-8018; 1873-5258
• DOI: 10.1016/j.oceaneng.2023.115171

The seabed seismic analysis of a viscoelastic half-space with overlying liquid under two-dimensional (2D) oblique incident P- or SV-waves is performed by the finite/infinite element method (FIEM). Firstly, the exact solutions of the free-field solid-liquid responses in frequency domain are derived for the waves with arbitrary incident angles, including the critical angles of reflection for SV-waves and of transmission for P- and SV-waves. Next, the equivalent seismic forces to be imposed on the near-field boundaries are computed for the solid and liquid assuming that the earthquake data are available on the solid-liquid interface. Then, the equations of motion for the seabed modeled by the finite/infinite elements are presented with the solid-liquid interface implemented and the key parameters selected. The reliability of the solutions has been verified by comparison with Wolf's in frequency domain, and by inversely computing the input ground motions in time domain. New findings from this paper include: (1) The suppressive frequencies exist in the presence of overlying liquid, for which the vertical solid displacements are reduced for P- and SV-waves both for under-critical cases. (2) Both the horizontal and vertical displacements of the solid surface are reduced by overlying liquid for SV-waves with over-critical incident angles. •Derive newly the exact solutions for free-field solid-liquid responses for oblique incident P or SV waves.•Identify firstly critical angles of transmission for both P and SV waves.•Derive equivalent seismic forces for liquid for oblique incident waves.•Use finite/infinite element method for undersea seismic analysis for oblique incident waves.•Suppressive frequencies exist for vertical solid displacement for P and SV waves both for under-critical cases.