Collapse loess is a special structured soil because of its special sediment environments. When moisture and stress suffered from changing

macromechanical characteristics would change significantly. To analyze the stress-strain relationship changing laws and structural damage evaluations of loess under moisture and stress coupling effect

the sub-loading surface and super-loading surface ideas are introduced into soil constitutive model by Asaoka et al

in this paper

based on the original super-consolidation parameter and structural damage evaluation parameter

the effect of water content changing is considered in super-loading and sub-loading surface constitutive model; and new initial super-consolidation parameter and structural damage evaluation parameter are defined. Base on the sub-loading surface and super-loading surface ideas

the general stress-strain relationships are derived by introducing structural index and structure yield strength into constitutive model; at the same time

the effects of parameters are analyzed. Finally

the accuracy and rationality of the constitutive model proposed are verified by comparing with experimental results of collapse loess in oedometer tests and conventional triaxial tests conditions and calculating results of constitutive model proposed in this paper.