Abstract: An elastic-plastic model for transversely isotropic geostructures is developed based on the Cosserat continuum. In the model， the elastic constitutive relationship is described by 5 deformation parameters and the Drucker-Prager yield criterion is extended by introducing fabric tensor and loading direction in the plastic stage. The iterative format for return mapping algorithms and the tangent modulus matrix are formulated for the proposed model. The numerical simulation is implemented based on the user subroutine (UEL) of ABAQUS， and a plane strain 8-noded reduced integrated element is used. The influence of the material principal direction and the anisotropic degree on the strain localization and the bearing capacity of the structure are analyzed. Numerical results show the validity and performance of the proposed model in simulating the strain localization behavior of transversely isotropic geostructures. Furthermore， the mesh dependency accompanied with strain localization is effectively solved.

Key words: geostructures, transversely isotropy, Cosserat continuum, strain localization, ultimate bearing capacity, numerical simulation