Research on Nonlinear Viscoelastic Creep Characteristic of Frozen Soft Rock of Cretaceous Formation

Creep curves at different temperatures and stress-strain isochrones were abtained by using uniaxial creep test for frozen soft rocks of Cretaceous formation. The test results showed that the creep process was nonlinear,and the viscoelastic creep compliance was related to time and stress. On the basis of generalized Kelvin model,the nonlinear viscoelastic creep expression was proposed by nonlinear improvement on creep compliance and the parameters were also identified. Through the comparison between the theoretical curves and the test results,the correctness and rationality of the model are verified.