Study On Spring Isolated Frame Foundation Model Of Turbinegenerators Of A Nuclear Power Plant

Our country is putting great efforts to construct nuclear plants at present,accompanying with which is the rapid increase of the number of stream turbineswith huge power. The research on and development of stream tubines with higherunit power is the main direction of the future development of the stream turbine.Therefore, the spring vibration isolation technique is popularized extensively in thefield of the turbo generator foundation in recent years in our country. At present, theturbo generator foundation primaryly adopts the structure form of reinforcedconcrete frame. Dynamic properties of the foundation have closely effect on thestable running of the turbine unit as well as the safety of the whole power plant.Nowadays many theoritical research could be conducted using large FinitElement Software, with the gradually matured application of the large FE softwarein engineering structures. However, the advanced test means could make up theerrors induced by the assumption of the theory and the difference of model choosingmethods of different technicians. Beasides, it could realize the cross-validation ofthe theory and the test and ensure the reliability of the research.It’s not realistic to perform field test for the large scale Reinforced Concreteframe structure studied in this paper. Thus, it shows obvious superiority to buildreduced-size model to test the natural vibration characteristic and the seismicperformance, if allowed by the test condition.Based on the above description, this thesis conducted detailed and throughexperimental and numerical simulation research on the vibration isolation andseismic performance of the spring vibration isolation foundation, based on the unit3and4project (2×1000MW) of the Tianwan Nuclear Power Plant. The main worksare as follows:Part1: Design and build1:8scale model in accordance with the originalstructural drawings;Part2: perform the vibration test with the transient-exciting method whichexcits and collects response at three-direction, and obtain the natural vibrationcharacteristics of the foundation (natural frequency, vibration mode, dampingratio);Part3: conduct the vibration analysis of the forced vibration response(vibration displacement and velocity) based on the above testing results to get thevibration response of the foundation under the running status of the unit; obtain thevalue and curve of the dynamic stiffness of the foundtaion when the unit runing atthe range of±25%(20Hz-30Hz) of the working speed by exciting and testing the bearing pedestal at the same point; examine the vibration isolation efficiency of thevibration isolation componets installed in3directions of the column head byhammering method;Part4: perform the model test of the foundation subjected to frequentearthquake, design earthquake and rare earthquake, respectively, according to theseismic conditions, measure the strength performance of steel bars, responses suchas the seismic acceleraton and displacement, the seismic performance, crack and theinterstory drift angle;Part5: numerically simulate the dynamic characteristics and thepseudo-dynamic test of the foundation using the explicit finite element softwareLS-DYNA, conduct paramenter analysis again based on the simulation to verify theconclusion of the test.