Abstract: To simulate the seismic ground motion history in liquefiable soil layers, a revised effective stress method is proposed and verified. In the revised method, the non-linear behavior of soils and the process of rigidity attenuation due to liquefaction are considered by iteration in every stress cycle. The model which can calculate the water pressure of saturated sands under anisotropic consolidation is used in the calculation procedure. The method and procedure presented here are tested by comparing with the post-earthquake records and shaking table tests. The comparative results show that the calculated results are agreeable with the actual records and the shaking table tests on main features, such as the PGA, the changes of the acceleration histories during the liquefaction process, the time-frequency history and response spectra. Especially, the calculated results quite correspond to those of the shaking table tests for the liquefaction-induced increment of the acceleration response spectra. As a result, the revised method presented in this paper is practical to simulate the seismic ground motion in the liquefiable soil layers.

Key words: liquefaction, seismic ground motion, simulation, effective stress, cycle-by-cycle