在土体主应力方向的旋转过程中,主应力方向与塑性主应变增量方向之间存在非共轴现象,传统的共轴本构理论无法合理描述非共轴现象及其对应力-应变关系的影响。通过有限元二次开发,在应变软化共轴模型的基础上引入了角点结构非共轴理论,对密砂的单剪试验进行数值模拟及分析,系统地研究了非共轴现象及其影响。数值分析结果与试验结果的对比表明:非共轴模型能够合理地反映非共轴现象及其影响,且非共轴现象受到静止侧压力系数、竖向应力和流动法则等因素的显著影响。
In the process of rotation of the orientation of principal stress, the non-coaxial phenomenon exists between the orientations of the principal stress and plastic strain rate. However, the traditional constitutive theory could not reflect the non-coaxial phenomenon and its influence on the relationship between stress and strain. The yield vertex non-coaxial theory is adopted into a strain softening coaxial model to research the non-coaxial phenomenon and its influence in the numerical simulations of simple shear test on dense sand. Comparison between numerical result and test result suggests that the non-coaxial model could reflect the non-coaxial phenomenon and its influence reasonably, and also, the roles of non-coaxial model are considerably influenced by static lateral pressure coefficients, vertical stress and flow rules.
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