  Large-deformation localized failure in geomaterials plays a crucial role in
geohazards engineering. This article investigates shear bands and retrogressive
failure of geomaterials through a recently formulated
large-deformation-plasticity periporomechanics (PPM) paradigm.
Periporomechanics is a nonlocal reformulation of classical poromechanics
through the effective force and peridynamic state concepts. The nonlocal
deformation gradient is multiplicatively decomposed into the elastic and
plastic parts in this large-deformation PPM paradigm. The stabilized
correspondence principle is adopted to implement a classical elastoplastic
constitutive model into the new PPM paradigm. We have numerically implemented
this large-deformation plasticity PPM paradigm through a Lagrangian meshfree
method in space and an explicit Newmark scheme in time. The implemented PPM
framework is used to model shear banding and retrogressive slope failure in
porous media under dry conditions. The numerical results have demonstrated the
efficacy and robustness of this new PPM paradigm for modeling shear banding and
retrogressive failure involving large deformation in porous media.
