Based on the theory of X-ray stress measurement, a method of measurement and representation for the inter-phase stress of double-phase material was established.

But the comparison of corresponding stresses derived from the two yield criteria in the σ2-σr coordinate is very simple and clear.

Based on governing equations of saturated porous media and Liapunov s stability here,onset conditions matrix of porous media used by solid stress and Terzaghi s effective stress constitutive description under seepage flow state,are presented,which have different forms with different representation of the solid phase,matrix or skeleton,constitutive model of porous media.