With the rapid development of underground space, more adverse site conditions are occurring in the construction of underground structures. For example, a subway station passes through longitudinally inhomogeneous geology. When the subway station crosses the interface of soft soil and hard soil, this may lead to the destruction of underground structures. In this paper, three-dimensional (3D) nonlinear seismic response analysis of subway stations crossing longitudinally inhomogeneous geology subjected to obliquely incident P waves is presented based on actual engineering background. The earthquake input method for the longitudinally inhomogeneous site that transforms the site seismic response into an equivalent nodal load is first developed and verified. The viscous-spring artificial boundary is used to simulate the radiation damping effect of infinite domain media. Subsequently, the topographic and geological effects on seismic response of engineering site are investigated. Finally, the failure mechanism of the subway station structure crossing longitudinally inhomogeneous geology under the obliquely incident P waves is revealed. The investigation demonstrates that the plastic zone of site usually appears along the interface between the hard and soft soil media, and appears on the side of the soft soil. The sidewall and bottom slab of the structure experience obvious tensile damage at the interface location between the hard and soft soil media. The results show that topographic and geological effects should be considered in seismic analysis and design of underground structures when the topography and geology change significantly.

随着地下空间的快速发展，地下结构物的施工也出现了更多不利的场地条件。例如，地铁站穿过纵向非均质地质。当地铁站穿过软土和硬土的界面时，可能会导致地下结构的破坏。在本文中，基于实际工程背景，提出了地铁车站穿越纵向非均匀地质受斜入射 P 波作用的三维 (3D) 非线性地震响应分析。首次开发并验证了纵向非均匀场地的地震输入方法，该方法将场地地震响应转换为等效节点载荷。粘弹性人工边界用于模拟无限域介质的辐射阻尼效应。随后，研究了地形和地质对工程场地地震响应的影响。最后，揭示了地铁车站结构在斜入射P波作用下穿越纵向非均质地质的破坏机制。调查表明，场地的塑性区通常出现在软硬土介质的界面上，并出现在软土的一侧。结构的侧壁和底板在硬土和软土介质之间的界面位置受到明显的拉伸破坏。