Creep property is an important mechanical property of rocks. Given the complexity of rock masses, mechanical parameters\nchange with time in the creep process. In this work, a nonlinear function for describing the time-dependent change of parameters\nwas introduced and an improved variable-parameter nonlinear Nishihara shear creep model of rocks was established. By creating\nrock-like materials, the mechanical properties of rocks under the shear creep test condition were studied, and the deformation\ncharacteristics and long-term shear strength of rocks during creep were analyzed. The material parameters of the model were\nidentified using the creep test results. Comparison of the modelâ??s calculated values and experimental data indicated that the model\ncan describe the creep characteristics of rocks well, thus proving the correctness and rationality of the improved model. During\nshear creep, the mechanical properties of rocks have an aging effect and show hardening characteristics under low shear stress.\nFurthermore, according to the fact that Gk of the nonlinear model can characterize the creep deformation resistance, a method to\ndetermine the long-term shear strength is proposed.
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