Model And Application Of Dynamic Interaction Analysis Of Nuclear Power Structure Under Pile Foundation Conditions

The development of inland nuclear power is an important strategic decision of the state to optimize its energy structure and guarantee the power supply,ensuring the safety of nuclear power is an important cornerstone for the future development of inland nuclear power.The seismic adaptability analysis of the nuclear power plant structure under pile foundation has become an urgent technical problem to be solved in the process of inland nuclear power construction.Taking the AP1000 nuclear island plant as the research subject,the infinite foundatiom damping effect was simulated by using artificial viscoelastic boundary and the nonlinear characteristics of the soft soil was described by equivalent linear method.So that the refined numerical model for nuclear island structure-the end bearing pile-layered soil interaction was established.Through dynamic analysis and calculation under the action of earthquake,explore the seismic response of different pile foundation treatment methods to nuclear island plant.The specific research content includes the following aspects.Based on the analysis program of nuclear power structure-soil foundation dynamic interaction,this paper introduces the pardiso solver to improve the solution of the overall dynamic equation,thus,the calculation efficiency is greatly improved,and the program can be effectively applied to large-scale 3D dynamic finite element analysis.And through the free field response calculation,compare the average single-step analysis time and efficiency of ANSYS and this program.Based on wave field analysis of three-dimensional layered field,the rationality of the simulation of the ground fluctuation field and dynamic properties under the input of external ground motion is verified;Based on calculation of pile group foundation impedance function,the applicability of calculating dynamic response and the rationality of the grid scale under the condition of viscoelastic boundary is verified.On this basis,study the influence of the foundation treatment schemes of end bearing piles and CFG piles on the seismic response separately.Consider different structural forms of piles and rafts under the condition of end bearing piles,using the direct method of viscoelastic artificial boundary site coupling upper factory building structure,dynamic calculation are performed on the connected and disconnected piled raft foundation with cushion.The effects of different structural connection forms between the pile top and the raft on seismic response of nuclear island and internal force of pile were investigated.The dynamic time-history response calculation of the nuclear power structure after CFG pile foundation treatment was carried out,and compared with the floor response spectrum under the condition of end bearing pile;For the future possible scheme of laying vibration isolation piles around the nuclear island to form a more complete shock absorption system,a three-dimensional finite element model of vibration isolation pile and foundation is established.Through comparative analysis of the surface response under the action of earthquake,the earthquake resistant performance of the vibration isolation pile structure is preliminary explored.