双向振动条件下的饱和砂土动强度特性试验研究

利用全自动静动三轴双向耦合剪切仪,分别在均等固结和非均等固结条件下,进行了福建标准砂的动三轴不排水剪切试验,对比分析了轴向振动、径向振动、相位差分别为0°和180°的轴向-径向耦合振动等不同振动方式对饱和砂土动力特性的影响。试验结果表明,无论是均等固结还是非均等固结条件下,只要在最大剪应力面上的动剪应力水平相同,4种剪切方式对动应力-应变关系及动强度的影响都并不显著。

Experimental Study on Dynamic Strength Characters of Saturated Sandy Soils under Cyclic Bidirectional Loading

The Fully Automatic Static-dynamic Tri-axial Shear Apparatus is used to perform three-axis dy-namic shear tests for Fujian Standard sand under isotropic and anisotropic consolidation, and the dynamic characters of the saturated sand under different vibration modes are compared, such as axial vibration ,ra-dial vibration,axial-radial coupled vibration with phase angles 0°and 180°. It is shown that, on condition that dynamic deviator stress levels on the maximal shear stress surface are same, the influence of any of the four shearing modes on the dynamic stress-strain relationship and the dynamic strength is not signifi-cant no matter it is isotropic or anisotropic consolidation. Because the deviator stress level of the maximal shear stress is the combined action of axial and radial vibrations, the aseismic design without considering the cyclic axial stress is biased unsafe.