Cyclic Bi-Axial Tests on Assembly of Metal Rods Under Constant-Volume Condition to Study Re-Liquefaction Behavior
Cyclic Bi-Axial Tests on Assembly of Metal Rods Under Constant-Volume Condition to Study Re-Liquefaction Behavior
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DOI：
10.1007/s40515-020-00123-w
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发表时间：
2020-07
影响因子：
--
通讯作者：
J. Koseki;D. Yokoyama;T. Morimoto
中科院分区：
文献类型：
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作者：
J. Koseki;D. Yokoyama;T. Morimoto
作为桑迪再液化特性基础研究的一部分，进行了等体积条件下圆形截面铝合金棒组合的双轴循环试验，重点研究了液化前期应变幅的影响。通过对试样照片进行图像分析，评估和讨论了局部空隙条件的可能变化。结果表明，在液化前期，随着最大双振幅竖向应变从2.0%增加到7.5%，再液化抗力降低，这与以往砂土相关研究的结果一致。在液化阶段，观察到局部松动区的形成高达7.5%的双振幅垂直应变，这可能会影响随后的再液化阻力的下降。这些区域在再液化阶段部分地重新形成。通过液化后的再固结过程，可以观察到局部孔隙比变化的均匀性。除整体密实化外，这种变化可被视为导致抗再液化性增加的因素之一，如在高达2.0%和5.0%的双振幅垂直应变的液化阶段的试验中所观察到的。
As a part of fundamental studies on re-liquefaction behavior of sandy soils, cyclic bi-axial tests on assembly of aluminum rods having circular cross section were conducted under constant-volume condition, while focusing on the effects of strain amplitude during the previous liquefaction stage. By conducting image analyses on the specimen photos, possible changes in the local void conditions were evaluated and discussed. As a result, with increase in the maximum double amplitude vertical strain from 2.0 to 7.5% during the previous liquefaction stage, decrease in the re-liquefaction resistance was observed, which was consistent with results from past relevant studies on sands. Formation of locally loosened zone was observed during the liquefaction stage up to the double amplitude vertical strain of 7.5%, which may have affected the decrease in the subsequent re-liquefaction resistance. These zones were partly re-formed during the re-liquefaction stage. By the liquefaction history that was followed by re-consolidation, homogenization was observed in terms of the change of local void ratio. In addition to overall densification, such change may be regarded as one of the factors that would cause increase in the re-liquefaction resistance, as observed in the tests with liquefaction stages up to the double amplitude vertical strain of 2.0 and 5.0%.