# Study on the Influence of Deep Soil Liquefaction on the Seismic Response of Subway Stations
## 1 Introduction  
Earthquakes, with their suddenness, complexity, and severity, have severe impacts on human production and living conditions. Particularly in places with insufficient anti-seismic abilities and dense populations, the consequences caused by earthquakes are often extremely serious. Simultaneously, liquefaction behaviors triggered by earthquakes often lead to building collapse, underground facility damage, and other adverse results. Currently, the metro has become an important component of urban transportation. As areas where travelers gather and disperse, the seismic performance of metro stations, especially those located at liquefaction sites, is of particular importance. In recent years, scholars have carried out importance research focusing on the seismic responses and damage mechanisms of subway stations in liquefied layers, obtainingabundant research results. [PERSON], [PERSON], [PERSON], and [PERSON] et al. [1; 2; 3] analyzed the seismic response law of a hetero-span subway station in a liquefied field through the use of shaking table tests and numerical simulations; [PERSON], and [PERSON] et al. [4; 5] utilized a correlation analysis of the seismic responses of a subway station with irregular cross-sections in a liquefied site by means of shaking table tests; [PERSON] et al. [6] proposed and designed a replacement method for non-liquefied clay based on the concept of a \"resilient city\", and, through numerical simulation analysis, proved that this method has a good effect on resisting the liquefaction of the soil and reducing the uplift of the station structure; [PERSON] et al. [7; 8] conducted a detailed study on the seismic performance of monolayer two-span subway interval structures under different liquefaction location conditions through shaking table tests, and found that the liquefaction of soil at the bottom of the structure is the main cause of structural movement and inclined uplift; [PERSON] and [PERSON] et al. [9; 10] investigated the effect of liquefied interbedded soil on the seismic response of underground structures via centrifuge tests; [PERSON] [11] conducted a shaker test to investigate the seismic response of subway stations in liquefied soil layers; [PERSON] et al. [12] analyzed the seismic response of burial depth on subway stations in liquefied sites; [PERSON] et al. [13; 14; 15; 16; 17] studied the seismic performance of shield-expanded subway stations and frame subway stations in liquefied sites by means of shaking table tests and numerical simulations, investigating the damage mechanism of shield-expanded subway stations and the deformation mechanism of frame subway stations; [PERSON] et al. [18] conducted a numerical simulation to analyze the seismic response of a subway station embedded in saturated sand soil, revealing that the primary cause for the uplift of the station structure is the flow of liquefied sand soil beneath the station's base slab. Based on the analysis above, it can be seen that studies have been conducted by scholars regarding the seismic response and failure mechanisms of metro stations with different structural forms in liquefied sites, including unconnected stations, standard stations, shield-driven stations, and sectional structures. Meanwhile, research has also been performed focusing on the impact of liquefied layers on underground structures. Studies show that the liquefaction behavior of ground soils affects the horizontal deformation, vertical displacement, and acceleration responses of station structures. The main research methods include numerical simulations, shaking table tests, and centrifuge tests. Among them, numerical simulations are beneficial due to characteristics such as visualization, cost-effectiveness, and wide applicability. Before a project's construction, this method can help engineers predict the seismic performance of metro station structures, including displacements, accelerations, and stresses, which are crucial for the seismic design of metro stations.