Based　on　the　shaking　table　test　of　the　liquefiable　soil-piles-superstructure　system,　the　liquefaction　process　and　seismic　failure　mode　of　the　liquefiable　site　with　an　overlying　non-liquefiable　soil　layer,　as　well　as　the　instability　or　damage　mechanism　of　a　low　pile　cap-pile　group-superstructure　system　are　analyzed　by　a　two-dimensional　finite　element　model.　The　model　considers　the　post-liquefaction　shear　deformation　of　sand,　the　interface　models　for　the　pile　and　cap　with　the　liquefiable　and　non-liquefiable　soil,　and　the　interface　model　between　the　liquefiable　and　non-liquefiable　soil　to　account　for　the　discontinuity　of　interface　deformation.　The　typical　calculation　results,　including　the　excess　pore　pressures,　accelerations,　displacements　of　soil,　and　bending　moments　of　the　piles,　are　compared　with　the　experimental　results　to　verify　the　developed　models　and　reveal　the　effects　of　site　liquefaction　and　the　soil-structure　dynamic　interaction　on　the　seismic　responses　and　instability　mechanisms　of　the　piles-superstructure　system.　©　2023　Institution　of　Structural　Engineers