中文摘要：

我国南海分布有大量的钙质砂,在波浪或地震等动荷载作用下会发生液化。利用土工动力三轴仪进行了南海钙质砂的动力液化特性试验。试验表明,在等压固结条件下,不同围压下饱和钙质砂试样的变形模式基本相同,加载初期试样抵抗变形的能力较强,试样的应变幅值较小,孔隙水压力几乎呈单调上升,该阶段孔压仅有很小的波动,且动应变幅值几乎不发生变化。随后孔压发展进入加速阶段,试样软化明显。在循环加载过程中,剪缩与剪胀交替出现,孔隙水压力产生较大的波动,试样软化会使得剪应变持续增加,同时试样的剪胀反应又使每一循环中试样的液化趋势减弱,变形发展受到抑制。

英文摘要：

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.