Influence of inherent anisotropy on the seismic behavior of liquefiable sandy level ground

摘要

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. (C) 2019 Production and hosting by Elsevier B.V. on behalf of The Japanese Geotechnical Society.