The relation between liquefaction resistance and shear wave velocity for new and old deposits
The relation between liquefaction resistance and shear wave velocity for new and old deposits
复制标题
新老矿床液化阻力与剪切波速的关系
DOI：
10.1016/j.sandf.2016.04.016
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发表时间：
2016
影响因子：
3.7
通讯作者：
H. Bilsel
中科院分区：
文献类型：
--
作者：
Roozbeh Safaeian Amoly;K. Ishihara;H. Bilsel
对取自2011年东日本大地震时已知液化地区的桑迪原状和重塑试样进行了多系列循环三轴试验。在该试验方案中，首先测量剪切波速，然后施加循环荷载来确定循环剪切强度。未受扰动的样品分为两组，一组来自古老的冲积层（更新世）深层沉积物，另一组来自近地表浅层，这些样品显然受到2011年事件液化的干扰。由此获得的数据被绘制成循环强度与剪切波速度的关系图，并通过两组土的曲线图中的平均点绘制两条曲线，即一条为原状土，另一条为扰动土。结果发现，对于一个给定的循环强度，剪切波速度确实有倾向变得更大的未受干扰的样品从老存款相比，未受干扰的样品从表面上的剪切扰动样品。还对几个完全扰动状态的砂样进行了类似的实验室试验。这些重构样品的测试结果的曲线图也显示了在循环强度和剪切波速度之间的关系的趋势，这是相似的，从原位沉积物中回收的剪切扰动样品。为了理解上述观察的结果，将来自剪切波速的循环强度和剪切模量之间的比率作为参数，以区分上述两种不同的关系。该比值可称为“屈服应变”的“参考应变”，用于解释循环强度和剪切波速度之间的相关性差异。
Multiple series of cyclic triaxial tests were performed on undisturbed and reconstituted samples of sandy soils obtained from areas of known liquefaction at the time of the 2011 East Japan Earthquake. In this test scheme, the shear wave velocity was firstly measured and then cyclic loads were applied to determine the cyclic shear strength. The undisturbed samples were classified into two groups, namely, one from old alluvial (Pleistocene) deep deposits and the other from near-surface shallow depths which had apparently been disturbed by the liquefaction in the 2011 event. The data thus obtained were plotted in terms of the cyclic strength versus the shear wave velocity, and two curved lines were drawn through average points in the plot for the two groups of soils, that is, one for the undisturbed soils and the other for the liquefaction-disturbed soils. It was found that for a given cyclic strength, the shear wave velocity does have the propensity to become larger for the undisturbed samples from the old deposits in comparison to the undisturbed samples from the seemingly liquefaction-disturbed samples. Similar sets of laboratory tests were also performed on several sand samples reconstituted to a completely disturbed state. The plots of the test results for these reconstituted samples also showed a tendency in the relation between the cyclic strength and the shear wave velocity which is similar to that for the liquefaction-disturbed samples recovered from the in-situ deposits. In order to understand the outcome of the above observations, the ratio between the cyclic strength and the shear modulus from the shear wave velocity was taken as a parameter to distinguish the two different relations as mentioned above. This ratio, which might be called the “reference strain” of the “yield strain”, is used to provide an interpretation of the difference in correlation between the cyclic strength and the shear wave velocity.