| Recently, the haze pollution of China is increasingly serious and received extensive attention, speeding up the "nuclear energy development" strategy was back on the agenda. With the growing demand of energy, clean energy represented by the nuclear power plays a more and more important role. But with the high quality site such as batholith becoming more and more scare, the suitable feasibility study of building nuclear power plants on deep overburden layer is imminent. Take a 180-meter deep non- lithology overburden layer nuclear site and the upper reactor building for studying, consider the nonlinear effect of soil under dynamic loads. Compile a C++ program in frequency-domain based on the equivalent linearization method and the one-dimensional shear wave propagation theory, the time-domain model of equivalent linearization method is achieved with the secondary development of general software ANSYS, compare the dynamic response of free-field which is calculated by the self-made program with SHAKE91 which is widely used in engineering, it proves that the self-made program is reasonable. Finally, make a comparison of the floor response spectrum of nuclear power plant that is calculated respectively under the batholith and deep overburden lithology site condition, and discussed the impact of the deep overburden layer to the seismic response of the upper nuclear power structure. It specifically includes the following aspects:(1) Introduce the superiority and rationality of Duncan-Chang model which is representative in the foundation static model in engineering, make a brief contrast and introduction for the Duncan-Chang E-v model and the E-B model, according to the Duncan-Chang E-v model theory, achieved the calculation program on the platform of ANSYS, and consider the actual situation that the upper part structure load is stepwise applied to the foundation. Conduct the static calculation for a deep overburden layer foundation of a nuclear power plant, and get the displacement and stress results of the static foundation model.(2) Introduce the equivalent linearization method theory which is widely used in engineering. Mainly analyze the development status and the advantages and disadvantages of this method, and introduce the basic principle of equivalent linearization method briefly. According to the equivalent linearization method and one-dimensional shear wave propagation, compile an equivalent linearization method calculation program in frequency domain on the platform of C++, the influence factors of the dynamic response of free-field under layered foundation have been discussed, finally we make a contrast by an example between the widely used SHAKE91 and the C++ program, it verifies the accuracy of the C++ program and also provide some reference to the achievement of equivalent linearization method in time-domain.(3) Combine the equivalent linearization method with the progressive integration theory in time domain, the time-domain model of equivalent linearization method is achieved with the secondary development of ANSYS. The 3 dimensional finite element model of site soil is established, the restriction of the bottom and side surface of the model is determined according to different seismic wave input model. Select the mesh size according to the material properties of the foundation, make sure that the main frequency component of the seismic wave can pass through. The establishment of time-domain model, process of model boundary, equivalent of seismic wave input and the damping calculation method are introduced and discussed in detail in the implementation process of the time domain method.(4) Compare the floor response spectrum of the nuclear power structure on bedrock condition with the result on deep overburden layer condition at the selected points, a brief analysis is conducted for the influence of the deep overburden layer on the seismic response of upper structure. |
PDF Full Text Request