Based on two-dimensional Cosserat constitutive model for layered rockmass

a new three-dimensional expanded Cosserat medium constitutive model

in which the influence of meso bending was taken into account

was proposed for layered salt rock containing two alternate layers with mismatch mechanical properties. It was validated primarily by an experiment on laminated salt rock samples under uniaxial compression. By using this new model

it can be analyzed the influence on stiffness of layered salt rock of the presence of hard or soft interlayer and also the macroscopical isotropy of layered salt rock due to interlayer. Combined with conventional strength theories

this model can be utilized further through a routine way for the strength and failure analysis. The proposed model can be expanded to solve nonlinear problems directly

and can be embedded to numerical analytical software for analysis of the stability of complicated underground openings in laminated salt rock.