Abstract：The nonstationary probabilistic seismic response was carried out via pseudo excitation algorithm combined with finite element method under uniform nonstationary seismic environment. The evolutionary power spectral density (PSD) of acceleration at the engineering bedrock was handled as the nonstationary pseudo input. Shear modulus and damping ratio were obtained iteratively from the Hardin-Drnevich constitute relationship accounting for the nonlinearity of soil and the effect of pore pressure. Also，the performance of four techniques，using different approximations to estimate the equivalent peak value of shear stress and strain，were investigated for the purpose of determining the equivalent shear modulus，damping and excess pore water pressure induced by seismic loading，in which the equivalent peak value is computed in terms of its standard deviation and the corresponding peak factor. It is found that the interpolation method based on probabilistic average approach is appropriate compared to the deterministic method. The analytic results indicate that the dynamic response of liquefiable soil is time-dependent due to the cumulation of the excess water pore pressure and should be considered as nonstationary process.
