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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。
There is a large amount of calcareous sand distributed in the South China Sea, where liquefaction occurs under dynamic loads such as waves or earthquakes. The dynamic liquefaction of calcareous sand in the South China Sea was carried out by means of geotechnical triaxial apparatus. The results show that the deformation modes of saturated calcareous sand under different confining pressure are basically the same under the condition of equal pressure consolidation, the deformation resistance of specimens is stronger during initial loading, the strain amplitude of specimen is smaller, the pore water pressure Almost monotonically increased, the pore pressure at this stage only a small fluctuations, and almost no change in the amplitude of dynamic strain. After that, pore pressure development has entered an accelerated phase and the sample softens obviously. In the process of cyclic loading, shearing shrinkage and dilatancy alternately appear, the pore water pressure produces greater fluctuation, the softening of the specimen will make the shear strain continue to increase, and the dilatancy reaction of the specimen causes the liquefaction of the specimen in each cycle The trend is weakened and the development of deformation is suppressed.