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修正了传统隐式回映算法,建立了适用于饱和黏土循环动力分析的边界面塑性模型的完全隐式积分格式。该模型基于无弹性域概念和临界状态理论,采用各向同性、运动硬化准则、旋转的边界面,并引入表征土体结构损伤和重塑程度的损伤变量以反映循环载荷作用下饱和黏土的各向异性、刚度、强度软化及塑性变形累积等特征。针对等压固结0K?1.0和偏压固结0K?0.67的饱和高岭黏土的不排水三轴试验进行模拟,采用不同的应变增量步长进行计算,并与试验数据对比,结果表明,修正隐式回映算法应用于该类边界面模型的合理性、积分格式的精确性和稳定性;另外,结合有限元软件自动时间步长的增量迭代解法,对饱和黏土应力控制的不排水动三轴试验进行预测,结果表明,修正的适用于该边界面的塑性模型隐式回映算法可以得到比较合理的数值分析结果,能够反映饱和黏土的循环刚度的退化和强度的弱化等动力特性。
The traditional implicit mapping algorithm is modified, and a completely implicit integral scheme is established for the plastic model of interface plasticity. The model is based on the concept of inelastic domain and the critical state theory. The isotropic, kinematic hardening criterion, the rotating boundary surface are introduced. The damage variables that characterize the degree of damage and remodeling of soil structure are introduced to reflect the effects of each To the opposite sex, stiffness, strength and plastic deformation and other characteristics of plastic deformation. The undrained triaxial tests of saturated kaolin clay with equal pressure consolidation (0K? 1.0) and saturated consolidation of 0K? 0.67 were simulated and calculated using different increment of strain increment. Compared with the experimental data, In addition, the incremental iteration method of finite element software with automatic time-step is applied to correct the rationality of the implicit mapping algorithm and the accuracy and stability of the integral format. The results show that the modified plastic model implicit mapping algorithm applied to the boundary surface can get more reasonable numerical analysis results and can reflect the dynamic characteristics of the saturated clay such as degradation of the cyclic stiffness and weakening of the strength .