Seismic Response Analysis Of Marine Engineering Structures

With the implementation of the “Belt and Road”,China will build a large number of Marine engineering structures.However,China's coastal areas are on the Pacific Rim seismic belt,one of the two major seismic belts in the world.The potential seismic danger is very large.How to ensure the seismic safety of Marine engineering structures during service is of great significance.Due to the influence of seawater,the seismic response analysis of Marine engineering structures involves fluid-solid coupling problems,which is very complicated.This paper studies the seismic response analysis of the Marine site and the Marine engineering structure,respectively.The main work is as follows:(1)In fact,when porosity equals to one and zero,the saturated porous media is reduced to fluid and solid respectively.Based on this idea,firstly the Biot's equations are approximated by Galerkin scheme and the explicit lumped-mass FEM is chosen.Then considering the conditions of coupling on the irregular interface between porous media with different porosity,by solving the normal and tangential interface forces,the coupled algorithm is derived,which is proved to be suitable for the coupling between fluid,solid and saturated porous media.Thus,the coupling problem between fluid,solid and saturated porous media can be brought into a unified framework,in which only the solver of saturated porous media is used.The three-dimensional code for this proposed method is programed.Considering the situation of sag terrain in water-bedrock,water-saturated seabed-bedrock system,the effectiveness of the unified computing framework and the feasibility of parallel computing are verified.(2)The free field obtained by the Thomson-Haskell transfer matrix method is used as input,and the infinite domain is simulated by the transmission artificial boundary.The internal domain adopts the fluid-solid coupling unified computational framework to provide technology for seismic wave field simulation of complex medium and complex terrain in the sea.The effectiveness of the method is verified by a basin-shaped depression seabed topography,and the seismic scattering of the saturated seabed is further analyzed.(3)Based on the unified calculation framework of fluid-solid coupling of irregular interfaces,and the use of zoning algorithms for sea area and structure calculation,the seismic response analysis of seawater-seabed-structure system is realized.Taking an offshore single-pile wind turbine as an example,the response of an offshore single-pile wind turbine in the case of P pulse wave incidence was calculated,and the responses of the foundation and the superstructure were analyzed,and the response of the offshore structure under the input of ground motion is further analyzed.