Abstract
This paper presents an integrated numerical algorithm based on the nonlinear augmented finite element method (N-AFEM) to accurately simulate the arbitrary evolving strong discontinuities (cracks/slip lines) and failure behaviors in geotechnical structures. A novel nonlinear elemental augmentation and condensation scheme was first proposed within the N-AFEM framework, which allows the consideration of nonlinear coupled intra-element cracks without the need of additional nodes or nodal DoFs. Then a modified exponential cohesive zone model (CZM) that considers the coupling effects between tension/compression and shear at the fracture surface was proposed to describe the fracture process of geomaterials. Besides, a nonlinear yielding function based on the Mohr-Coulomb strength theory was introduced into the framework and serves as the fracture initiation criteria for geomaterials. Finally, several benchmark examples were simulated and the predicted results were compared with existing numerical or experimental data to demonstrate the validity of the proposed method.
•A nonlinear elemental augmentation scheme is proposed to account for intra-element cracks without additional nodal DoFs.•A CZM that considers the coupling effects between tension/compression and shear at the fracture surface is formulated.•A nonlinear yield function based on Mohr-Coulomb theory is introduced as fracture initiation criteria for geomaterials.•The fracture behaviors and failure mechanisms of several benchmark examples are investigated in detail.
