Calcareous sand is widely distributed in the South China Sea.It will be liquefied under the wave or seismic loading.In this paper

the dynamic liquefaction characteristics of the calcareous sand was investigated by using the dynamic triaxial apparatus.The test results show that the deformation patterns of the saturated calcareous sand samples under different confining pressure are similar in the condition of isobaric consolidation.The calcareous sand has a higher deformation resistance in the initial loading stage

and the pore water pressure is linearly built up with the loading cycles.There is no obvious change of the dynamic strain amplitude in this stage.And then

with the cycles increasing

the pore pressure builds up quickly and the sample shows an obvious softening.In the cycle loading

the positive and negative dilation appears alternatively

and the pore water pressure has larger fluctuations.The shear strain increases continuously with the softening of the sample.Meanwhile

the positive dilation of the sample can lead to weaker trend of the liquefaction

and restrains the deformation of the sample.