Experimental and constitutive model study on the mechanical properties of the structural plane of a rock mass under dynamic disturbance

Accurate description of the mechanical properties and deformation characteristics of the structural plane of a large chamber or slope rock mass under the ultimate stress with periodic stress disturbances is of great significance to ensure the stability and safety of underground rock engineering. By theoretically analyzing the strength effect of the structural face of a rock mass under dynamic disturbance, a criterion for the occurrence of shear damage on the structural face of a compressed rock mass under dynamic disturbance is proposed. The results of the cyclic disturbance kinetic test show that there is a disturbance threshold for the shear failure of the structural plane under different disturbance stresses. When the disturbance stress is lower than the disturbance threshold, Cumulative plastic strain stabilizes with increasing number of cycles; when the disturbance stress is higher than the disturbance threshold, S-shaped curve of cumulative plastic strain versus number of cycles. Revealing the progressive damage process and mechanism of rock structure surface under periodic dynamic disturbance. Based on the perturbation concept theory, the relationship between the accumulated plastic strain and the number of cyclic loading is similar to the relationship between strain and time in the creep curve of rocks, a new nonlinear viscous element is proposed, and the nonlinear element and the deformation element considering structural surface closure and sliding are combined with the Burgers model to form an 8-element nonlinear viscoelastic-plastic creep constitutive model. Using the global optimization algorithm of 1stOpt, the model validation and parameter identification are performed on the experimental data, and the results show that the model curve has a very good agreement with the experimental data. The model can accurately reflect the deformation characteristics of the structural plane of a rock mass under periodic dynamic disturbance. The research results give a new idea to analyze power disturbance-induced geohazards.