Numerical Simulation of Rock Fracture and Permeability Characteristics under Stress-Seepage-Damage Coupling Action

In the field of rock mechanics, the stress-seepage-damage coupling numerical simulation of rock has always been a hot topic but a difficult problem. Based on this background, we newly derive the smoothed particle hydrodynamics (SPH) form of the seepage equation and a two-dimensional (2D) stress-seepage-damage coupling constitutive model. The proposed coupling model considers the heterogeneity of the engineering rock mass and overcomes the difficulty of the conventional SPH algorithm in stress-seepage-damage calculation. Stable one-dimensional (1D) seepage is first simulated to verify the correctness of the seepage equation and that the simulation results coincide with traditional analytical solutions. Then two triaxial compression experiments considering seepage and no-seepage conditions are simulated to show that the coupled model can well simulate the progressive rock failure process and the change in permeability. The correctness of the coupling model is verified by comparing the simulated results with experimental results. The existence of a seepage field advances the initial cracking time and weakens the peak strength of the rock. Finally, the progressive damage processes of surrounding rock excavation under unloading action are simulated, showing that stress-seepage-damage coupling model has application prospects in rock engineering. The research results may provide some references for the application of the SPH method in the stress-seepage-damage coupling simulation of rock.