含弱渗透性覆盖层饱和砂土地震液化特性研究

针对含弱渗透性覆盖层的饱和砂土地基进行一组离心机振动台试验,并采用OpenSees对试验模型进行数值模拟。通过模型试验与数值模拟结果对比讨论OpenSees对于饱和砂土地基地震液化模拟的精度;采用水平方向的Arias强度表示传入某一位置的地震动强度,并以液化时水平方向Arias强度作为该土层的抗液化强度;采用OpenSees计算不同地震动输入时饱和砂土的反应,以此检验Arias强度作为抗液化强度的准确性。结果表明,引起饱和砂土液化所需要的地震动强度随深度增加而增加;当传入的地震强度达到砂土发生液化所需要的地震强度时,该层砂土将会发生液化。

Seismic Liquefaction Characteristics of Saturated Sand with a Low Permeable Covering Layer

In this paper, a group of centrifuge-shaking table tests were performed for saturated sand with a weak permeable covering layer. OpenSees was used to carry out the numerical simulation on the test model. Experimental and numerical results were compared and discussed. The horizontal Arias Intensity (I_a) was used to measure ground motion intensity. When liquefaction occurred, the horizontal I_a was taken as the anti-liquefaction strength of the soil. The reaction of saturated sand subjected to different earthquake waves was calculated by OpenSees to test the accuracy of I_a as a measure of anti-liquefaction strength. Results showed that ground motion intensity, which can cause liquefaction of saturated sand, increases with increasing depth. When incident seismic intensity reached the requirement for the liquefaction of sand, liquefaction occurred.