Assessment for stability of based on clayey sail deposits during earthauake by on-line pseudo dynamic response test

由于软粘土地基层既放大又衰减地面运动，因此需要了解非线性对地表地震反应的影响。另一个明显减弱地面运动的现象是桑迪层的液化。液化地基刚度急剧下降，阻碍剪切波向上层传播，从而降低地震反应加速度。在1995年兵库县南部地震中，出现了液化衰减地震运动的典型例子。在这次地震中，发生了液化，对港口设施和填海造岛造成了不同程度的破坏。在日本，各种结构的抗震设计标准在这次地震后都进行了修订。为了准确研究粘土固结度对砂土交替层振动特性的影响，对粘土-砂土交替层进行了在线拟动力响应试验。通过改变粘土层的厚度和排列顺序，研究了粘土层对交替层液化和地震反应特性的影响

Since soft clay ground layers both amplify and attenuate ground motion, the effects of the nonlinearity on the earthquake response of the ground surface needs to be understood. Another phenomenon that notably attenuates ground motion is liquefaction of sandy layers. Liquefied ground shows drastic drops in stiffness, impedes propagation of shearing waves to upper layers, and thus reduces the earthquake response acceleration. Typical examples of attenuated earthquake motion by liquefaction were seen during the 1995 Hyogo-ken Nanbu Earthquake. During this earthquake, liquefaction occurred and caused various degrees of damages to port facilities and reclaimed artificial islands. In Japan, seismic design standards for various structures have been revised after this earthquake. On-line pseudo-dynamic response tests were performed on the alternating layers of clay and sand in order to precisely investigate the effects of the degree of consolidation of clay on the vibration properties of the alternating layers in the present study. Tests were also conducted by changing the thickness and order of the clay layer to investigate the effects of the clay layer on the liquefaction and earthquake response characteristics of the alternating layers