Abstract
Strain localization is often recognized as prefracturing processes of soil and rock materials and has been extensively investigated so far. However, most of the investigations employed the classical constitutive equation, and hence the strain localization zones were found to be essentially dependent on the size of the finite elements. In the present investigation, a viscoplastic constitutive equation is generalized by introducing the strain gradient into the equivalent stress. The numerical results of plane strain finite element simulation of a uniaxial compression test on rocks are presented. The influences of the strain gradient, the finite element mesh size and the size of the specimens on the strain localization are discussed.
