不同应力路径下剪切带的数值模拟

采用回映应力更新算法，编写了基于伏斯列夫面的超固结黏土本构关系模型子程序，嵌入非线性有限元软件ABAQUS。通过对单元试验进行三轴压缩、三轴伸长及平面应变等问题的模型预测，再现了超固结黏土在不同初始超固结比和应力路径时的变形和强度特性，从而验证了子程序的正确性。借助该本构模型，对三轴压缩、三轴伸长及平面应变应力路径下超固结黏土体变形局部化问题，进行了三维数值模拟。分析结果表明：超固结黏土在三轴压缩及伸长状态时，土体变形局部化在应力-应变关系软化时出现，而平面应变状态时，在应力-应变关系硬化阶段出现，其超固结黏土的剪胀特性在剪切带的形成过程中起重要作用。

Numerical simulations of shear bands along different stress paths

In order to apply an elastoplastic constitutive model for overconsolidated clay based on the revised Hvorslev envelope to numerical analysis of shear bands, a subroutine is developed for the implementation of the model into a nonlinear finite element software ABAQUS by using the return mapping algorithm. Numerical simulations of triaxial compression, triaxial extension and plane strain tests are performed. The algorithm is verified by simulating the mechanical behaviour of overconsolidated clay with different initial overconsolidation ratios. By using the implemented program, three-dimensional finite element analysis of shear band is carried out under triaxial compression, triaxial extension and plane strain stress paths. The numerical results show that, onset of strain localization occurs in the softening regime under triaxial compression and triaxial extension conditions; and under plane strain condition onset of the strain localization occurs in hardening regime; and the shear dilatancy of overconsolidated clay plays an important effect on the formation of shear bands.