Analysis on Propagation Characteristics of Rayleigh Waves in Ocean Sites and Their Influence Parameters

Abstract

To study the propagation and attenuation characteristics of Rayleigh waves on the irregular seabed in saturated elastic half-space，a simplified dynamic model of irregular seabed sites is established with the fundamental equation of soil dynamics proposed by Zienkiewicz. By changing the boundary conditions，the Rayleigh equations are derived for the degradation model of uncovered seawater and overlying seawater when the water-soil contact interface is flat. And the dispersion and attenuation curves of Rayleigh waves under the influence of permeability coefficient，porosity，Poisson's ratio，and interface conditions are given. Based on the complex sea bed model，the effect of various factors on the dynamic response of seabed parameters，such as pore pressure and deformation during Rayleigh wave propagation，is analyzed. The results show that the soil mechanical parameters，such as elasticity modulus，permeability coefficient，and porosity，as well as the overlying water and the interface of sediment water，all affect the dynamic response of the seabed. The influence range and extent of different Rayleigh wave velocities on soil mechanical parameters differ along the soil depth. Elastic modulus and Poisson's ratio are important parameters that determine the properties of soil and are prerequisites for discussing the propagation characteristics of Rayleigh waves and the dynamic response of the soil. Their change affects the influence law of permeability coefficient，porosity，and other parameters. In the two simplified models，when the elastic modulus of the rock stratum is 6.017×1010 Pa and Poisson’s ratio is 0.38，the porosity and permeability coefficient have regular effects on the propagation characteristics of Rayleigh waves.