地基自由场离心机振动台模型试验研究

在清华大学土工离心机实验室50g 离心场环境中进行了一系列地基自由场离心机振动台试验。试验包括1个砂土地基、1个黏土地基和2个成层土地基振动台试验。试验中模型箱采用叠环式模型箱，其平面尺寸为0.5 m和0.2 m，试验中输入地震波采用Kobe波和Parkfield波。给出了部分试验结果分析，包括加速度时程及频谱反应、加速度峰值放大系数和土层中剪应力-剪应变变化曲线。试验结果发现，不同类型地基中加速度反应存在差异，在低频部分加速度峰值放大系数从底部到顶部逐渐增大。土体中剪应力-剪应变变化规律在砂土地基和黏土地基中存在差异。

Dynamic centrifuge model tests on an unconfined soil foundation

A series of centrifuge shaking table tests on soil deposits are conducted under gravitational fields of 50gat the Institute of Geotechnical Engineering in Tsinghua University. The tests include 1 sand deposit model, 1 clay deposit model and 2 layered deposit models. They are performed using a laminar shear box with plan dimensions of 0.5 m and 0.2 m respectively, and the test system is subjected to strong ground motions, Kobe waves and Parkfield waves. Partial test results are presented, including acceleration responses, Fourier spectra of accelerations, amplification factors of peak accelerations and shear stress-strain histories. The test results indicate that the acceleration responses vary in different types of soil deposits. The amplification factors increase with the decreasing depth in low frequency. And the shear stress-strain histories show discrepancy in sand and clay deposits.