各向异性地基条件下条形基础动力试验研究

地震液化现象一直是土动力学里的一个热门研究课题，前期研究表明由砂土颗粒之间接触的法向分布和颗粒形状所引起的内在各向异性会对砂土动力学特性会有影响。而现有的液化判别方法没有考虑砂土的内在各向异性，使得地震对上部结构的影响很难准确的评价，本研究通过专门设计的离心机模型箱控制砂土的不同沉积方向模拟地基的内在各向异性，并且通过6个离心机振动模型试验研究各向异性的砂土地基对条形基础的动力学特性的影响，包括条形基础的加速度、水平位移的影响。与前期的无条形基础的研究结果相似，在饱和情况下，砂土的内在各向异性对条形基础的动力学特性影响非常大，加速度和超孔隙水压力表明，沉积方向为90o的地基使得条形基础的破坏较为严重，引发严重的地表沉降和基础的水平残余位移。为了更加准确的预测结构物在地震区的动力特性，此研究结果显示应在工程勘察对地基的评价进行修正。

Dynamic Behavior of Strip Foundation on Anisotropic Ground

Liquefaction of sand is the main cause of failure for earth structure during the earthquake. Some past research showed that fabric anisotropy of sand due to contact normal distribution and particle shape may affect the seismic response. Current assessment of liquefaction potential did not account for the fabric anisotropic so that the settlement of structure could not be predicted reasonably. To explore the effects of fabric anisotropy on dynamic response of strip foundation and anisotropic ground, in this study, six centrifuge tests were performed on scaled model by ground prepared in different deposition angles. A special rigid container was designed and used to prepare models with different directions of soil deposition. It was found that fabric anisotropy significantly influenced the dynamic response of strip foundation and ground. The liquefaction resistance of model of 90°is lower than those of other models from observation of acceleration and pore pressure evolution, which were indicated by serious settlement and residual horizontal displacement. The results recommended that to precisely predict the dynamic performance of structure, the effect of fabric anisotropy on dynamic response of ground should be incorporated in the conventional design method, which significantly affected the settlement and liquefaction resistance of ground.