由于液化后应力应变行为模拟的困难及数值计算的不稳定性,可液化土层中地下结构的动力反应分析是岩土工程的难点课题之一。基于作者提出的能够模拟饱和砂土液化后大应变响应的弹塑性循环本构模型,采用完全耦合的饱和土动力反应分析程序,对阪神地震中破坏的大开车站进行分析,说明考虑液化变形的土与地下结构动力相互作用分析方法及其有效性。从饱和砂土单元在液化过程中的应力应变响应角度,揭示了地层和车站的大剪切变形与饱和砂层液化程度的关系,分析了大开车站地震破坏的原因。
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 HyogokenoNambu 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.