Abstract: In engineering region, the equivalent linearization method is often used to the nonlinear seismic response analysis of soil layers in 1 D; but when the large peak acceleration time period is chosen as the computing input for taking account of load on site in large earthquake event, the method brings the remarkable “resonance” effect, which results to the mistakes in the evaluation to the surface response. For estimating the nonlinear seismic response more exactly, it is recommended to a true nonlinear method in time domain fitting curve and curve, and using it to 1D nonlinear seismic response analysis of soil layers on Xiangtang Array. In the study, the true nonlinear results of surface seismic response comparing with the results from the equivalent linearization method and actual records, the feasibility of the recommended method is proved. And the numerical studies show that the recommended method is more reasonable than the equivalent linearization method in large earthquake cases.

Key words: nonlinear seismic response analysis, equivalent linearization method, true nonlinear method, normalization spectra ratio