Numerical simulation of strain localization through an integrated Cosserat continuum theory and strong discontinuity approach.

In this paper, we propose a new numerical approach abbreviated as Cos-SDA for analyzing strain localization problems of geomaterials. The Cos-SDA is achieved by implanting the strong discontinuity approach (SDA) into the computational framework of the Cosserat continuum finite element approach (Cos-FEA). Through two numerical examples of plane strain compression test and slope stability, it is demonstrated that the Cos-SDA model can effectively simulate the entire progressive failure process of geomaterials from weak discontinuity to strong discontinuity. Cos-SDA can effectively alleviate the influence of mesh distortion in shear zone, and the numerical solution can still maintain convergence even under large deformation. Cos-FEA and Cos-SDA have much stiffer mechanical response than SDA-FEA since an internal length scale is introduced into the governing equations. In contrast, the SDA-FEA shows more conservative as the unmature bifurcation occurs and weak discontinuous stage is ignored in the numerical simulation, while Cos-FEA numerical results show an over-stiff mechanical response in the stage of post failure. Cos-SDA inherits the advantages of both SDA-FEA and Cos-FEA and neutralizes their mechanical responses, so it is more reasonable in simulating the progressive failure process from weak discontinuity deformation (strain localization) to strong discontinuity deformation (slip) occurring in geomaerials. [ABSTRACT FROM AUTHOR]