复杂应力条件下掺砾黏土真三轴试验

采用新型真三轴仪器，对掺砾黏土进行了复杂应力条件下加载试验，近似模拟了土石坝填筑期心墙土体单元的加荷过程。试验结果表明，由于土体单元处于复杂应力状态，即使是单向加载这样的简单加荷应力路径，在不同应力方向上的应力和变形也都呈现显著的应力各向异性。土石坝应力变形分析中坝体单元处于三向应力条件下，由于加载引起的应力各向异性对心墙乃至整个坝体的应力变形规律都有较大影响，合理的本构模型应该能够反映并描述这种复杂应力状态下的应力各向异性。

True triaxial test on clay mixed with gravel under complex stress state

A new kind of true triaxial apparatus is introduced. To simulate the loading process of core wall element under the dam construction process, true triaxial tests on clay mixed with gravel soil were carried out under complex stress state, which can simulate the practical stress path to some extent. It was found that even for single axial load applied from the major principal stress direction, because of the influence of initial complex stress state, the stress induced anisotropy effects are remarkable. There are different relationships between stress and strain in different principal stresses directions. Based on the testing results, it is suggested that when carrying out the numerical analysis of dam, the stress induced anisotropy should be taken into consideration, so as to reasonably describe the practical behaviors of the core and the whole dam body under three dimensional complex stress states.