应力路径对重塑粘土本构关系影响的试验研究

为探讨应力路径对重塑粘土本构关系的影响,进行了增、等、减排水和常规三轴压缩不排水应力路径下的三轴压缩试验,获得了四种应力路径下重塑粘土的应力应变关系,采用数值建模方法通过可视化分别给出了四种应力路径下整个应力场中的剪切和体积三维变形曲面,并给出了四种应力路径下的剪切和体积屈服轨迹。对比这四种应力路径下的变形结果发现,无论在应力范围、应变峰值、应变曲面的形状和体积屈服轨迹的变化趋势上都存在显著差别,然而剪切屈服轨迹相似。这些结果证实了应力路径对粘土本构关系的影响是相当大的和不容忽视的,而有效平均正应力对应力路径相关性的影响是决定性的。

Experimental Study on Influence of Stress Path on the Constitutive Relations for Reshaped Clay

In order to study the influence of stress path on the constitutive relations for reshaped clay,the triaxial compression tests under stress paths with drainage in cases of increased,constant and decreased mean normal stress and undrained conventional triaxial compression test have been carried out,the stress-strain relations under the four stress paths are obtained.Through visualization the three-dimensional surfaces of shear and volume strain in the whole stress field under the four stress paths are given respectively by numerical modeling.In addition,the four families of shear and volume yield loci are plotted respectively.It is found through comparing the deformation results under the four stress paths that there are obvious differences in the stress ranges,the strain peaks,the shapes of strain surfaces and the trends of variation of volume yield loci,however,for the four families the shear yield loci are similar.These results demonstrate that the influence of stress path on the constitutive relations of clay is considerably large and could not be neglected,and it relates to the effective mean normal stress closely.