Seawater-Seabed-Structure Dynamic Interaction Analysis

In order to adapt to the "The Belt And Road" development strategy and promote the sustainable and healthy development of the Marine economy,China will build a large number of Marine engineering structures.However,China's coastal areas are located in the Pacific rim seismic belt,the potential seismic risk is very large.How to ensure the seismic safety of Marine engineering structures in service is an important problem.Because of the sea water,The analysis of seismic input and structural response is much more complex than that of the terrestrial case.Taking the seismic response analysis of Marine engineering structures as the objective,the free field analysis,finite element analysis of Marine sites and interaction analysis of seawater-seabed-structures are studied respectively in this paper.The main work is as follows:(1)Based on potential flow theory and Biot porous media model,the dynamic response of seawater-seabed-bedrock system under plane P/SV wave incidence was analyzed.According to the interface continuity between ideal fluid,saturated seabed and elastic bedrock,the steady state response of saturated seabed and the overlying seawater layer can be obtained by Thomson Haskell transfer matrix method,and the transient response in time domain can be obtained by Fourier inversion.The influences of the incident Angle,the thickness of seawater layer and other relevant parameters on the free field response are further analyzed.(2)The ideal fluid,solid as the special circumstances of saturated porous media,based on the saturated porous media equation,considering the coupling between different porosity of saturated porous media,the general situation,set up the situation of the concentrate quality explicit finite element method,the coupling between fluid and solid,saturated porous media problem into a unified computing framework,and the corresponding three-dimensional parallel analysis program.The effectiveness of the unified computing framework and the feasibility of parallel computing are verified by corresponding examples.(3)Considering the continuous conditions at different media interfaces,the seawater-seabed-structure interaction analysis is realized.Taking a pier structure as an example,considering the situation of linear seabed and nonlinear seabed respectively,the reaction of seawater-seabed-pier system in the case of P/SV pulse wave incident is calculated,and the effect of pier on the reaction of seawater-bedrock system is analyzed by comparing with the free field reaction.The linear and nonlinear responses of seabed soil are further compared.The pore pressure distribution and cumulative dissipation process in seabed soil under nonlinear condition are analyzed.