  We study a strain gradient-enhanced version of a model for geomaterials under
compression by Marigo and Kazymyrenko (2019) coupling damage and small-strain
associative plasticity. We prove that the jumps in time of the plastic variable
may happen only along jumps of the damage variable. Moreover, we perform a
vanishing-viscosity analysis showing existence of Balanced Viscosity
quasistatic solutions \`a la Mielke-Rossi-Savar\'e.
