Investigation On A Turbin-Generator Foundation Operation And Seismic Safety Performances Of Large Power Plant

As an important structure to bear the upper unit equipment,the turbine-generator foundation request rather highly for the dynamic characteristics and seismic security in view of the fact that its own structural complexities and particularities.In fact,compared with the restriction of field measurement and the theoretical error of numerical simulation,model testing can reflect the dynamic response and seismic response exactly and actually for large steam turbine-generator unit.Based on this,operation safety and anti-seismic safety of the steam turbine-generator foundation can be evaluated scientifically.On the basis of a certain power plant project in Hebei province,which is a large turbine-generator foundation with installed capacity of two million kilowatts,a 1:10 scale model was designed and established in accordance with similarity relation.Aimed at this experimental model,following studies were carried out.(1)With the transient-exciting method,we can obtain the natural vibration characteristics of the foundation,which including freequency,mode shape and damping ratio.The numerical model with the same size were established based on finite element software.By comparing the calculation results with experimental data and combining theoretical analysis and experimental study,the dynamic characteristics of the foundation can be comprehensively analyzed in the end.(2)By testing the dynamic stiffness of bearing block where has disturbing opoint,the bearing block's deformation performance in resisting dynamic loading can be verified.(3)By means of model synthetic-analytical techniques,the forced vibration response of the foundation under the action of the disturbance force can be predicted and a scientific evaluation of the operation safety of the unit is also provided.(4)During the pseudo dynamic testing,by loading 7 degree frequency and rarely occurred artificial earthquake waves on the foundation,the structural response,plastic(5)deformation and crack development of the structure was collected.(6)Through the pseudo static testing,seismic performance of the model structure under low frequency cyclic action would be studied,which includes ultimate bearing capacity,hysteretic and skeleton curve,ductility coefficient,and stiffness degradation etc.As a result,the aseismic safety characteristics of the turbo-generator foundation would be evaluated as well at last.The analysis proved that the foundation worked well and met the standard 'Code for seismic design of buildings'.Under the action of vertical load brought by unit operation and horizontal earthquake,the ability of deformation can be fulfilled the Code.At the same time,the model testing data can be provided by studing this type of foundationin the future,and the conclusion has important application value in engineering practice.