Generalized Kelvin Creep Damage Model and Its Parameters' Intelligent Identification

In order to describe the characteristics of rock rheological deformation better, a generalized Kelvin creep damage model considering the deterioration effects in creep process was proposed, and its finite difference scheme was derived. Based on the interface platform of software FLAC3D, the model was developed using C++ language. Furthermore, an intelligent algorithm combining PSO (particle swarm optimization) algorithm, SA (simulated annealing) algorithm and FLAC3D was put forward and adopted to determine the rheological parameters in the model based on the existing experimental data. The research results show that the proposed model can reflect visco-elastic-plastic properties and damage characteristics of rock, and simulate the two-stage creep effect of rock in a low stress condition and three-stage creep effect of rock in a high stress condition. The algorithm can converge to the global optimal solution in some 40 steps as long as inversion parameters are selected appropriately.