Past seismic events have shown that caisson quay walls are susceptible to severe damage during earthquakes, underscoring the importance of assessing their seismic behavior. However, very limited studies have been conducted on the soil-structure-water interaction of the caisson-ground system during earthquakes. This study will investigate the seismic response and failure mechanism of a caisson through a centrifuge shake-table test. Specifically, the seismic response results of the backfill, the caisson, and the subsoil are discussed; an acceleration integration method for identifying permanent displacement to estimate the backfill deformation is proposed; and a phase analysis of the seismic response of the caisson-ground system is conducted. It is found that the liquefaction of the backfill results in a substantial increase in the dynamic earth pressure behind the caisson. The failure mode of the caisson is lateral movement accompanied by slight tilting and continuous rocking vibrations. The proposed acceleration integration method can effectively estimate the deformation and lateral spreading of backfill. Phase analysis results reveal the relationship between the failure of the caisson-ground system and seismic action.
