Based on the shear creep curves of gray marbles contain green schist weak structural plane

using rock biaxial rheology testing machine

the long-term strength and accelerated creep properties are studied. On this basis

a new nonlinear shear rheology component is proposed. When nonlinear rheological model component serial connected with Nishihara model

a new nonlinear visco- elastoplastic shear rheological model can be built to fully describe the shear creep properties of greenschist weak structural plane. Using complete accelerative rheological curve

the nonlinear visco-elastoplastic shear rheological model is carried out the identification

and the correlative parameters of nonlinear rheological model such as viscoelastic modulus and viscosity etc. are also gained. The comparison between the rheological model and experimental result shows that the nonlinear rheological model is right and reasonable.