A method for the non-stationary stochastic seismic analysis is developed on basis of the general stochastic seismic motion model proposed by the first author to account for the randomness of the seismic loading as well as the non-stationarity of the stochastic process in the aspects of its intensity and frequency spectrum

and has been applied in a dynamic analysis of a homogeneous earth dam with the pseudo excitation method.The dam-foundation system is discretized by the finite element method

and its material nonlinearity is considered with the method of equivalent linearization.Firstly

the input time-frequency evolutionary power spectrum is defined according to the intensity and energy information of target acceleration history.Secondly

the seismic performances of the earth dam during the frequency non-stationary seismic excitations are discussed through comparing the results from determinate time-history analysis and stochastic analysis.Finally

the dynamic dam-foundation interaction is discussed through comparing the seismic responses of the dam under two different conditions of the foundation.The analysis results indicate that the frequency non-stationarity of the seismic motion has some influence on the dynamic response of the dam.In different phases of the earthquake process

effects of the dynamic dam-foundation interaction are different.The interaction is rather prominent in the main shock phase.