On localization in saturated porous continua

Localization in elastic-plastic saturated porous media is investigated here using a linear perturbation approach. The adopted localization criterion c orresponds to unbounded growth of perturbations. The critical conditions ar e compared with those obtained by a classical band analysis. While for one phase materials these conditions coincide, in the present context the linea r perturbation approach leads in the limit of unbounded growth to the singu larity of the undrained acoustic tensor, while the band analysis leads to t he singularity of the drained acoustic tensor. Some general results clarify ing the hierarchy of these two conditions are established for a guile gener al set of constitutive equations. (C) 2000 Academie des sciences/Editions s cientifiques et medicales Elsevier SAS.