中文摘要：

基于ABAQUS有限元软件平台，应用流固耦合两相介质动力模型孔压单元模拟场地饱和土体，进行了饱和土体-地下结构地震反应的计算研究。结果表明：在地震输入的最后时刻结构的两侧底角区域应力值最大；土体的孔隙压力和竖向位移主要集中在结构下方的区域，结构两侧土体的孔压与竖向位移呈对称分布；场地土体的竖向位移随深度的增加逐渐减小；体系最大地震反应出现的时刻对应于输入地震动的最大加速度出现的时刻。表明了流固耦合两相介质动力模型孔压单元在饱和土体-地下结构体系地震反应研究中的有效性。

英文摘要：

In China, various transportation facilities have been built on a large scale. Sea-crossing tunnel projects are constructed in many coastal cities, and many underground structures are built on the soft soil foundation in the south region. These are all underground structures on saturated soil, and China lies in the Pacific Ring of Fire, with many cities located in the high-intensity earthquake zone, so the seismic security of underground structures such as tunnels and subway stations is an important subject. The key is to make an accurate calculation of the dynamic re- sponse of the underground structure to the earthquake load. The dynamic response of an under- ground structure in a saturated soil site is very different from that in other types of soil sites. Therefore, the seismic response of underground structure in the saturated soil should be studied with the right calculation model and analyzing method. At present, one widely used method is numerical simulation and calculation. Depending on the soil calculation model it employs, the analytic method can be classified into three types： the total stress method, simplified effective stress method, and fluid-solid coupling dynamic model method. The fluid-solid coupling model, which takes into account the coupling of fluid-solid dynamic response, is a theoretically complete calculation model. Therefore, the method based on the fluid-solid coupling dynamic model is theoretically sound and more accurate. In general, the dynamic response of an underground structure in a saturated soil site needs further study. In this paper, the seismic response of an underground structure in saturated soil is studied based on the fluid-solid coupling dynamic model and ABAQUS in order to get a complete view of the character- istics and rules of the seismic response. We conduct a simulated calculation of the seismic response of an underground structure in saturated soil, with the site soil simulated by the pore pressure element deduced from the fluid- solid coupling dynamic model o