A creep constitutive model for heterogeneous frozen clay soil considering the damage of cryostructure

In cold regions, the creep behavior of frozen soil is a crucial indicator for evaluating the stability of engineering foundations. The creep properties of frozen soil are more complex than unfrozen soil owing to its special cryogenic structures. In this research, a series of creep tests were conducted on the heterogeneous frozen clay soil under different deviatoric stresses, and the influence of deviatoric stress and structural features on its creep behaviors were analyzed. Based on the test results and fracture mechanics, the damage variable of heterogeneous frozen clay soil considering the effect of cryostructure was defined, and the sensitivity of parameters in damage variable were analyzed. By introducing the hardening variable and damage variable into the classical Nishihara model, a new creep constitutive model for heterogeneous frozen clay soil considering the fracture of cryostructure was established, the validity of the model was verified using test results, and the model parameters were analyzed.