循环荷载对饱和黄土动剪模量的影响研究

利用装有压电陶瓷弯曲元的双向振动三轴仪对饱和黄土进行了循环荷载试验,并根据静力固结条件下黄土的动剪模量发展规律建立了基于哈定方程的拟合曲线;将循环荷载作用下的动剪模量与静力固结下的动剪模量进行了对比研究,并根据轴向应变的发展规律,确定了以上2种条件下动剪模量产生差异的原因：试样结构性破坏,土颗粒重排列,土体具有很高的敏感性。对于振动过程中的暂停对试验的影响进行了研究,认为由于暂停时间很短,可以忽略这种影响。在振动结束后,对试样在原压力下重新进行固结,结果表明,固结完成后,试样的动剪模量增大,且增大幅度随着密度的增加而变小。

Influence of Cyclic Loading on Dynamic Shear Modulus of Saturated Loess

Cyclic loading test of loess was conducted in use of bidirectional vibration＇ s triaxial test device with piezoelectric ceramic bending element. According to development rule of dynamic shear modulus of loess under static consolidation condition, the Hardin and Richart equation-based fitting curve was estab- lished. Comparison of dynamic shear modulus under cyclic loading and static consolidation condition was carried out and in the basis of development rule of axial strain, the reason of difference between both was determir~ed, i.e. sampler s structural damage, soil particle＇ s rearrangement and the high sensitivity of the soil body. The influence of pause process on test result was researched. It can be known that because the pause time is short, its influence can be ignored. After the test is over, the sample was consolidated under original pressure. The results show that after finish of consolidation, the dynamic shear modulus of the sample increases, but the increment decreases with increase of density.