Triaxial rheology characteristics and model of carbonaceous shale in pressure water

Firstly, by use of the mechanical testing & simulation system, the trialxial rheology curves of dry carbonaceous shale and carbonaceous shale in pressure water are obtained and the difference of rheology properties is compared and analyzed. Secondly, a linear viscoelastoplastic model is put forward to describe the rheology properties of shale in pressure water, thus the constitutive equation and creep equation are solved. Finally, the parameters of rheology model are achieved. The test results show that the pressure water reduces the yielding strength and raises the rheology characteristics of carbonaceous shale. The comparison between the rheology model and the experiment results shows that the linear viscoelasticoplastic model can reflect the deceleration and constant creep period, and can be used to study the rheology properties of shale or other rock in confined water.