Shaking table model test for seismic response of a pile group foundation with liquefiable sandy soil

In order to study dynamic characteristics of a pile foundation with liquefiable sandy soil under seismic loading,the four working conditions were studied including natural foundation,pile foundations with 3D,3.5D and 4D(D is the pile diameter) pile spaces by means of indoor shaking table model test.Initial effective stresses,time histories of excess pore water pressure and time histories of settlement during vibrations were determined with sensors.At the same time,the vertical bearing capacities of the pile reinforced foundations after vibrations were compared with those before vibrations.The test results showed that the liquefaction of soil for pile reinforced foundations delays compared with that of the natural foundation,and the pile foundations with 3D and 3.5D can more significantly improve liquefaction resistance;the vertical dynamic bearing capacity of the pile foundation with 3D is higher according to the largest settlement during vibration;all the vertical bearing capacities of pile foundations become larger after vibration.Based on the test,the pilesoil-structure dynamic interaction was understood more deeply during liquefaction of soil.The results provided a reference for optimal design of pile foundations.