Dynamic vertical impedance of a submarine strip foundation in ocean engineering: Water wave pressure effect

Many papers in the literature present studies of the interaction of sea waves, structures, and soil; however, most of these studies focus on the pore pressures and stresses in the soil around structures. Very little knowledge has been obtained regarding the impedance of a foundation considering the coupling of the water wave pressure effect (WPE) and dynamic soil-structure interaction (DSSI), as classical impedance functions are obtained based on a foundation on an elastic half-space with a stress-free surface. Impedance functions can be used to study the dynamic responses of a structure using the substructure method during the serviceability limit state design. This paper studies the forced vertical vibration of a strip foundation on a poro-elastic seabed with surface subjected to water wave pressures. The strip foundation on the seabed is simultaneously excited by water wave and other external forces at the same frequencies as water waves (with WPE-DSSI coupled). Three new impedance functions for foundations in ocean engineering are defined. Selected results for the new impedance functions are examined based on different water depth, wave height, wave frequency, and poroelastic material. The results show that for a rigid strip foundation in ocean engineering, both its total impedance and effective impedance are displacement dependent.