Secondary Development of a Nonlinear Creep Model Based on Fractional Derivative in FLAC3D

Time-dependent deformation behavior of rock has a significant impact on the stability of rock slopes or underground constructions, and more and more attention is paid to the research of creep models. Newton dashpots of burger-creep model in FLAC3D were replaced by abel dashpots. A nonlinear creep model was put forward based on fractional derivative. The finite difference scheme of the creep model was deduced for three-dimensional state. Using secondary development program interface of FLAC3D with the VC++, the program of user-defined model was developed. The reasonability and reliability of the model were verified by axial compression creep test of rock. The results show that the nonlinear model can describe the visco-elasticity, plasticity of rock. The research results promote the progress of secondary development of creep models and can provide references for similar models.