Seismic response analysis of a subway station in liquefiable soil

Soil-structure dynamic response analysis in liquefiable soil is a difficult problem due to the difficulty of modeling the post-liquefaction behavior and the instability of numerical calculation. A cyclic elasto-plasticity model developed by the authors, which can describe the large strain behavior during an entire liquefaction process, has been implemented in a fully coupled finite element program. The seismic response of Daikai subway station subjected to the 1995 Hyogoken-Nambu Earthquake is investigated to illustrate the philosophy of soil-structure dynamic response analysis with emphasis on soil liquefaction and also to validate its effectiveness. The calculated stress-strain curves and effective stress paths of typical soil elements are given to reveal the relationship of the large lateral deformation of the station and surrounding soil with the liquefaction extent of sandy stratum. It is found that liquefaction-induced large deformation may be the main reason causing serious damage to the Daikai station during the earthquake.