中文摘要：

利用GDS动三轴试验系统采用等幅循环应变加载方式对含有不同厚度粉土的饱和层状砂土进行了液化强度试验。分析了均匀砂和含有不同粉粒层厚度的层状砂土在循环荷载作用下的变形和力学特性。试验分析表明：由于含粉粒夹层的层状土特殊的土体结构，其孔隙水压力发展规律与一般的无黏性砂土不同；饱和层状砂土的抗液化强度并不是随着粉粒层厚度的增加而单调增加的，而是存在一个临界点；液化临界剪应变的大小与液化判别标准和循环次数有很大关系。试验结果表明，粉粒夹层对层状砂土的液化特性有很大的影响，且更能模拟自然环境条件下的层状砂土地基液化特性。

英文摘要：

Liquefaction strength tests for saturated stratified sands with different silty layer thicknesses were carried out by dynamic triaxial testing machine under constant stress amplitude cyclic loads. The deformation and mechanical properties for clean sand and stratified sand with different silty layer thickness were analyzed. The experimental results show that the development law of pore water pressure for stratified silty sands are different from clean sands due to the special soil structure; the liquefaction resistance strength of saturated stratified silty sands does not increase monotonously with the thickness of silty soil layer, but there is a critical thickness. However, the liquefaction resistance strength increases monotonously with the thickness increasing above the critical point; the critical shear strains are different under different liquefaction criteria and different cycle numbers, such as the critical shear strain under the criterion of △u/σ3c=1.0 is larger than that under the criterion of △u/σ3c =0.9. Besides, the critical shear strain should not be a constant under different earthquake magnitude and intensity. The silty interlayers influence the liquefaction characteristics of stratified silty sands greatly and can simulate the liquefaction characteristics of stratified sands in natural environment better.