Abstract In 2011 off the Pacific coast of Tohoku Earthquake, liquefaction and reliquefaction were observed along 600 km of the Northeast Coast of Japan and the infrastructure in this area experienced severe damage. During the earthquake, the fact that reliquefaction in aftershocks may also cause severe damage to infrastructure draws much attention of the researchers specialized in liquefaction. Researches in the literature indicated that if a sand experienced liquefaction, strong stress-induced anisotropy would occur, which could greatly influence the reliquefaction behavior of sand in aftershocks. Nevertheless, the influence of stress-induced anisotropy on mechanical behavior of sand subjected to cyclic loading has not yet been investigated in laboratory tests. For this reason, a systematic test program was conducted with sequential undrained triaxial cyclic loading tests on Toyoura sand, in which, all the samples were firstly subjected to the same undrained cyclic loading until liquefaction, after which the liquefied samples were fixed at different residual strain and consolidated. Then, the consolidated samples were again subjected to the cyclic loading under undrained condition. It is found that the residual strain will greatly influence the reliquefaction behavior of sand, which clearly indicates the importance of the stress-induced anisotropy formed during the first liquefaction. Based on the testing results, a new index for evaluating the reliquefaction resistance was proposed.

中文翻译：

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一种新的丰浦砂抗再液化性评价指标

摘要 2011年东北地震太平洋沿岸外，日本东北海岸600公里处出现液化和再液化现象，该地区基础设施受到严重破坏。在地震期间，余震中的再液化也可能对基础设施造成严重破坏，这一事实引起了液化研究人员的高度关注。文献研究表明，如果砂石发生液化，会产生强烈的应力诱导各向异性，这会极大地影响砂石在余震中的再液化行为。然而，应力引起的各向异性对循环荷载作用下砂土力学行为的影响尚未在实验室试验中进行研究。为此原因，在Toyoura砂上进行了连续不排水三轴循环加载试验的系统测试程序，其中所有样品首先经受相同的不排水循环加载直至液化，然后液化的样品在不同的残余应变下固定并固结。然后，固结的样品在不排水条件下再次经受循环载荷。发现残余应变将极大地影响砂的再液化行为，这清楚地表明在第一次液化过程中形成的应力诱导各向异性的重要性。根据试验结果，提出了评价抗再液化性能的新指标。所有样品首先经受相同的不排水循环加载直至液化，然后将液化后的样品固定在不同的残余应变下并固结。然后，固结的样品在不排水条件下再次经受循环载荷。发现残余应变将极大地影响砂的再液化行为，这清楚地表明在第一次液化过程中形成的应力诱导各向异性的重要性。根据试验结果，提出了评价抗再液化性能的新指标。所有样品首先经受相同的不排水循环加载直至液化，然后将液化后的样品固定在不同的残余应变下并固结。然后，固结的样品在不排水条件下再次经受循环载荷。发现残余应变将极大地影响砂的再液化行为，这清楚地表明在第一次液化过程中形成的应力诱导各向异性的重要性。根据试验结果，提出了评价抗再液化性能的新指标。发现残余应变将极大地影响砂的再液化行为，这清楚地表明在第一次液化过程中形成的应力诱导各向异性的重要性。根据试验结果，提出了评价抗再液化性能的新指标。发现残余应变将极大地影响砂的再液化行为，这清楚地表明在第一次液化过程中形成的应力诱导各向异性的重要性。根据试验结果，提出了评价抗再液化性能的新指标。