横观各向同性岩土材料的应变局部化分析

Numerical Analysis of Strain Localization for Transversely Isotropic Geomaterials

为分析横观各向同性岩土材料的应变局部化行为,推导对应于Lade横观各向同性屈服准则向前欧拉算法的迭代格式及本构矩阵,通过有限元软件ABAQUS的UMAT接口实现相应的程序代码。数值算例调查分析材料主方向对横观各向同性岩土结构的极限承载力和变形局部化模式的影响。结果表明该模型能较好地模拟横观各向同性岩土结构的应变局部化行为。

Geomaterials are usually transversely isotropic due to natural deposition.Their mechanical properties are obvious different along the deposition direction,however,substantially the same in the plane perpendicular to that direction.Anisotropic parameters such as fabric tensor,loading direction and stress state can be introduced to the isotropic strength criterion in order to simulate the anisotropic properties of geomaterials.In this study,in order to establish a criterion for transversely isotropic geomaterials,the anisotropic parameters such as anisotropic intensity and yield surface size are introduced into the Lade model.The iterative scheme corresponding to the forward Eulerian algorithm of Lade transversely isotropic yield criterion are presented.The influences of the principal axis direction on the bearing capacity of shear bands and structures are analyzed in numerical examples.Numerical results show the validity and performance of the proposed model in simulating the strain localization behavior of transversely isotropic geostructures.