Strain localization, usually manifesting as shear bands, is frequently observed in geomaterials and is of the essential reason inducing the failure of geostructures. Anisotropic characteristics of soils has an important effect on the shear band behavior. This paper is devoted to study the effect of the fabric anisotropy on the initiation and evolution of the shear bands. In particular, the anisotropy is introduced to the strength parameter of the yield criterion by incorporating the material principal direction and the joint invariant of the stress tensor and the microstructure tensor. Furtherly, an elasto-plastic constitutive model considering the fabric anisotropy is established in the micropolar theory framework, and is then applied to simulate the shear bands in transversely geomaterials via three numerical examples, including the plane strain compression test, slope stability and the shallow foundation problems. Moreover, the mesh independency of the proposed model is discussed. Results show that the bifurcation, the shear bands pattern, and the bearing capacity highly depend on the material principal orientation and the anisotropic degree. Comparison with existing study indicates that the proposed model has a good performance in simulating the typical pre and post strain localization behaviors of transversely isotropic geomaterials.

应变局部化，通常表现为剪切带，在岩土材料中经常观察到，是引起地质结构破坏的根本原因。土的各向异性特性对剪切带行为有重要影响。本文致力于研究织物各向异性对剪切带起始和演化的影响。特别地，通过结合材料主方向和应力张量和微观结构张量的联合不变量，将各向异性引入到屈服准则的强度参数中。进一步，在微极理论框架下建立了考虑织物各向异性的弹塑性本构模型，然后通过三个数值算例将其应用于模拟横向岩土材料中的剪切带，包括平面应变压缩试验、边坡稳定性和浅基础问题。此外，还讨论了所提出模型的网格独立性。结果表明，分叉、剪切带模式和承载力高度依赖于材料的主取向和各向异性程度。与已有研究对比表明，该模型在模拟横向各向同性地质材料典型的应变前后定位行为方面具有良好的性能。