双向耦合剪切条件下饱和砂土动强度特性试验研究

Dynamic strength of saturated sand under bi-directional cyclic loading

针对饱和粉细砂,利用双向耦合多功能剪切仪进行了均等固结条件下的循环耦合剪切试验。应用已有的动强度定义,着重研究了双向动荷载的相位差β,双向动荷载的幅值比值λ对砂土动强度及孔压特性的影响。实验结果表明,砂土液化动强度与相位差β及幅值之比λ密切相关,现有的动强度定义在复杂加载情况下具有一定局限性;双向动荷载相位差β以及幅值比值λ对孔隙水压力增长速度影响显著,但对归一化孔隙水压力发展模式没有显著的影响。

Using the vertical-torsional coupling shear apparatus,a set of bi-directional cyclic loading tests on saturated sand under isotropic consolidated condition are conducted.Based on the existing definitions of dynamic strength,the effects of phase difference of bi-directional dynamic load(λ) and ratio of bi-directional dynamic load amplitude(β) on dynamic strength and pore pressure of sand are studied.The test results show that the dynamic strength of liquefaction of saturated sand considerably relates with bothβ and λ.The existing definitions of dynamic strength have obvious limitation.The phase difference of bi-directional dynamic load(β) and the ratio of bi-directional dynamic load amplitude(λ) have significant influences on the growth rate of pore water pressure,while they have no significant influence on the development model for the normalized pore water pressure.