Three Dimensional Nonlinear Soil Structure Interaction Analysis In Time Domain

The analysis of soil structure interaction is an important part in the seismic design and safety assessment of nuclear power structure.SASSI software is usually used to analyze the soil structure interaction of nuclear power structures.The analysis process is conducted in the frequency domain,which can give reasonable results under small to moderate earthquakes.The equivalent linearization method is used to consider the nonlinearity of soil.But in recent years,strong earthquakes have occurred frequently,and many nuclear power stations have experienced strong earthquake records that are beyond design basis.Under strong earthquakes,the soil structure system will exhibit significant nonlinearity,such as the material nonlinearity of structure and soil,and the geometric nonlinearity of foundation.The theoretical basis of the frequency domain method is linear superposition,therefore SASSI is inherently unable to give reasonable results under intense earthquakes.Thus,the time domain analysis method needs to be developed.Due to its large amount of computation and lack of relevant experience,the method of nonlinear soil structure interaction analysis in time domain has been less used.And there is no widely accepted time domain method.In order to describe more accurately and accurately the response of nuclear power structures under strong earthquakes,a method of three-dimensional time-domain nonlinear analysis of soil structure interaction for nuclear power structures is presented in this paper,and the corresponding parallel analysis program is completed.The main work of this article is as follows:(1)A parallel algorithm for the analysis of soil structure interaction in time domain is proposed,and the corresponding analysis program has been completed.The computational efficiency of the algorithm is greatly improved by the parallel calculation of the soil partition and the dynamic analysis of soil and structure.(2)The Davidenkov backbone is adopted in the nonlinear soil constitutive model,accompanying with the modified Pyke's method.Nonlinear soil structure interaction analysis of a nuclear structure is carried out,and the results are compared with the results of linear soil structure interaction analysis,and the rationality of the analysis is verified.(3)The dynamic contact force model is used to consider the dynamic contact problem between foundation and soil.The nonlinear soil structure interaction analysis of cantilever column is carried out,and the rationality of the dynamic contact force model is verified,and the related parameter analysis is carried out.