Effect of pile foundation on seismic response of adjacent subway station buried in sand site by centrifuge shaking table tests

In densely built-up urban areas, subway stations are inevitably constructed adjacent to the pile foundations of high-rise buildings. The dynamic interaction between adjacent structures under seismic loading differs from that of isolated structures. This study employed a program of centrifugal shaking table tests to systematically investigate the seismic response of subway stations embedded in sand sites with and without an adjacent pile foundation. The influence mechanism of the pile foundation on the seismic response of the subway station was revealed. The results suggest that the pile foundation experiences significant settlement under seismic loading, thereby exerting compressive forces on the surrounding soil. The uplift of the subway station exacerbates, and the surface settlement on the side distant from the pile is restricted. The variation in the earth pressure in the vicinity of the pile increases and results in a slower recovery to the initial state. Although the installation of pile foundations slightly reduces the maximum excess pore water pressure ratio at the surrounding site, it causes the peak to occur earlier. As a result, the duration of the filtering effect of sand liquefaction on seismic waves is prolonged, thereby prominently reducing the acceleration amplification effect at shallow foundations. Concurrently, the structural deformation and the internal force of the subway station intensify, particularly at the middle column. These findings provide a basis for assessing the seismic performance of underground structures near high-rise building piles.