Abstract:

At present, most constitutive models are difficult to simultaneously reflect the creep behavior of soft and hard rocks, and their applicability is limited. To construct a more widely applicable rock creep model, based on the generalized Kelvin-Voigt model, the theory of fractional calculus operators and damage mechanics theory were introduced to construct a new rock fractional creep model considering time-dependent damage, which is extended to three-dimensional stress space. Model validation analysis is found that: 1) Simulating uniaxial compression creep tests on marble and triaxial compression creep tests on sandstone using newly constructed one-dimensional and three-dimensional models, the average R² (goodness of fit) was of 0.994 4 and 0.994 2 respectively, proving the feasibility of the newly constructed models; 2) At the same time, the newly established model and the fractional-order creep model in related literature were used to simulate the triaxial creep data of sandstone, and the average R² was 0.994 2 and 0.992 7, respectively, and the average R2 of the newly established model was 0.001 5 higher than that of the previous model; 3) The simulation of triaxial compression creep test data for four types of rock hardness, namely granite, slate, mudstone, and fully weathered granite, showed an average R² of 0.989 9, demonstrating the applicability of the new model.

Key words: time damage')">

time damage, rock, fractional order, creep, susceptibility