Influence of inherent anisotropy on the seismic behavior of liquefiable sandy level ground
Influence of inherent anisotropy on the seismic behavior of liquefiable sandy level ground
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DOI：
10.1016/j.sandf.2018.12.006
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发表时间：
2019-04
影响因子：
3.7
通讯作者：
K. Ueda;Keita Uratani;S. Iai
中科院分区：
文献类型：
--
作者：
K. Ueda;Keita Uratani;S. Iai
固有的各向异性是一个重要的方面，要考虑到更好地理解的强度和变形特性的粒状材料。自20世纪60年代中期以来，它一直是密集调查的焦点。然而，固有各向异性的影响，地面地震反应，如液化，尚未得到广泛的研究。本文通过一系列可液化砂层的动力离心模型试验，研究了固有各向异性对地面地震反应的影响。在模型设置过程中，使用专门设计的刚性容器实现了五种不同的沉积角度（0度、30度、45度、60度和90度）。模型暴露于锥形正弦输入加速度和记录的结果进行了充分的研究。结果发现，沉积角引起的固有各向异性显着影响振动和消散阶段的超孔隙水压力响应。超静孔压累积量和超静孔压持续时间随沉积角的增大而增大，而消散速率随沉积角的增大而减小。土体的各向异性也会影响土体的沉降，体积应变随沉降角的增大而沿着增大。关于响应加速度，固有各向异性的影响取决于超孔隙压力累积的量（即，液化程度）。鉴于这些结果，可以得出结论，以较高角度沉积的桑迪地面（即，接近90度），更容易发生液化，在评估液化潜力和进行有效应力分析时，应考虑固有各向异性的影响。
Inherent anisotropy is a crucial aspect to consider for an improved understanding of the strength and deformation characteristics of granular materials. It has been the focus of intense investigation since the mid-1960s. However, inherent anisotropy’s influence on ground seismic responses, such as liquefaction, has not been extensively studied. In this paper, inherent anisotropy’s influence on ground seismic responses is examined through a series of dynamic centrifuge model tests on liquefiable level sand deposits. During the model setup, five different deposition angles (0, 30, 45, 60, and 90 degrees) were achieved using a specially designed rigid container. The models were exposed to tapered sinusoidal input accelerations and the recorded results were fully investigated. It was found that deposition angle-caused inherent anisotropy significantly influenced the excess pore pressure responses during the shaking and dissipation phases. The amount of excess pore pressure build-up and the high excess pore pressure duration increased with the deposition angle, while the dissipation rate decreased as the deposition angle increased. The inherent anisotropy also influenced liquefaction-induced ground settlement, with volumetric strain increasing along with the deposition angle. With respect to response acceleration, inherent anisotropy’s effects depended on the amount of excess pore pressure build-up (i.e., degree of liquefaction). In view of these results, it was concluded that a sandy ground, deposited at a higher angle (i.e., closer to 90 degrees), is more susceptible to liquefaction and that inherent anisotropy’s influence should be considered when evaluating the liquefaction potential and performing effective stress analyses.