| With the reintroduction of energy strategy "to accelerate the development of nuclear power", nuclear energy becomes increasingly important in adjusting energy structure and implementing energy saving in China. Considering the fact that high quality of site condition, like rock foundations for nuclear plant is increasingly scarce and the development of inland nuclear power is in urgent need, it is significant to carry out the seismic adaptive analysis on non-nuclear power plant rock foundation. This paper is based on the adaptability of a nuclear power project in the200-meter-deep coverage under the conditions of land-based to construct CPR1000million-kilowatt nuclear power plant as the background; seismic numerical analysis model of nuclear reactions plant with soil foundation is studied, In which the characteristics of soil’s nonlinear dynamic was considered, the implementation is improved, the secondary development of ANSYS is used to calculate the nonlinear dynamic analysis of non-layered natural rock venue, and dynamic response of floor response spectrum is analyzed through establishing impedance substructure method of soil-structure interaction model. The main contents and results are concluded as follows:(1) According to Duncan Chang model of nonlinear elastic foundation and APDL in ANSYS, the computer simulation analysis program is completed. Considering that the gradual loading in construction process makes dynamically modifying the geotechnical parameters possible, the nonlinear calculation of rock-soil foundation is carried out. The problems in nonlinear finite element analysis and the corresponding modified methods are also discussed in this paper. The correctness of the model is verified through experimental simulation analysis. It provides the initial soil parameters and initial static field for the analysis of seismic condition with non-rock foundation.(2) The current research status of the response analysis method of ground seismic at domestic and abroad is summarized. The basic principles of the equivalent linear method which is widely used on engineering are briefly introduced. The advantages, disadvantages and the latest progress are displayed. By combining the one-dimensional shear wave propagation with the equivalent linear method, the correctness of my program is proved by comparing with SHAKE91program which is widely used around the world. The understanding of equivalent linear method is deepened.(3) The development status of equivalent linear method analysis software at home and abroad is presented briefly, and the advantages and disadvantages of each analysis software are considered. Based on the general software ANSYS, an improved time-domain model with the equivalent linear method is developed, which is more suitable for seismic load. The problem of material damping vaguely defined is solved in this model, the foundation parameters are considered during the start, intensity, attenuation of the earthquake, and the effects on the accuracy are studied. Through a multi-model comparison among shake91, GEODYNA and ANSYS analysis, the correctness of the model for the equivalent linearization method is verified. Considering the non-stationary factors over time history for the seismic energy, the overlapping unit, life and death unit and restart technology are adopted to solve the problem of lower shear modulus and higher damping ratio obtained from traditional equivalent linear method which makes the soil layer soften artificially. The final results are more accurate and reasonable.(4) The dynamic calculation model of floor spectra based on impedance substructure method is established to show how non-rock layered foundation affects structural dynamic response of the nuclear plant. The finite difference method is used to gain speed and acceleration response with compatible the dynamic post-processing mode of ANSYS. It is proved that this method is adaptive to make seismic analysis of nuclear power plant with non-rock foundation, by contrast with the results from GEODYNA software. |
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