Zagilsky V. Improvement of the computational method for the analysis of dynamical interaction of the "soil - foundation - structure" system for the nuclear power plants

The object of study - processes of interaction of elements of "soil - foundation - structure" system under seismic impact. The aim of the thesis is to improve the method of calculating the interaction of the elements of the "soil - foundation - structure" system under seismic impacts for buildings and nuclear power plants with a slab foundation, justification of the method and the development of its algorithm. Methods: the finite element method; verification calculations to verify the accuracy of the used software; experimental field studies of the interaction of soil and structures under dynamic impact, followed by the numerical calculations of the kinematic parameters of the building; mathematical modeling of tasks of the interaction of elements "soil - foundation - structure" system under the action of seismic loads using the improved method. Theoretical and practical results: the method of analysis of "soil - foundation - structure" system under seismic impacts, that takes into account the visco-elastic properties of the soil, is improved by combining analytical and numerical solutions, the application of the improved method in practice allows to calculate the floor spectra response of buildings and structures of NPP with a slab foundation; new data of full-scale field studies of the interaction of soil foundation with structure under the influence of periodic loads are received. Based on the obtained data the use of an improved method is justified; it is demonstrated for the first time that the use of an improved method for calculating the interaction between the soil and facilities allows us to calculate the spectra response of buildings in the areas of equipment location. Scientific novelty: new experimental data of amplitude and frequency characteristics of the building with slab foundation in a full-scale field studies of interaction with the subgrade construction at periodic loads are received; the method for calculating the interaction of the elements of the "soil - foundation - structure" system with dynamic action, taking into account viscoelastic properties of the soil basis, is improved, a combined algorithm for analytical and numerical solutions that can improve the efficiency of computation of floor response spectra of hard massive buildings with slab foundation is developed; the method for determining the natural vibration frequencies structures and soil by means of Fourier transform MS recordings is further developed. Degree of implementation: the results are used in the performance of work on the calculation of floor response spectra and maximum acceleration of buildings and structures of the South Ukrainian and Zaporizhzhian NPP. Scope of use: design organizations, construction laboratories in the calculation of seismic parameters of hard massive buildings with slab on soil base.