Onset condition of strain localization in saturated porous media

Based on governing equations of saturated porous media and Liapunov's stability, the onset strain localizations of porous media that formularized by solid phase stress and effective stress under seepage flow state are presented here. The onset strain localization conditions are different with expressions of governing equations of porous media and the constitutive model of porous media. With the derived onset strain localization condition of Terzaghi's effective stress, some failure modes in porous media caused by two kinds of relative movements between solid phase and fluid phase have been discussed by means of examples.