关键词: 衰减振荡扰动, 离散元, 蠕变特性, Burgers模型, 砂岩

Abstract: Mining disturbance can easily aggravate the creep instability of roadway surrounding rock, and its propagation mode in surrounding rock is damped oscillation disturbance. In order to explore the creep characteristics of rock under the damped oscillation disturbance, X-ray diffraction, nuclear magnetic resonance and pseudo-triaxial creep tests were carried out. Based on the test results, a discrete element numerical model of sandstone was established. The parameter calibration results show that the combination of linear parallel bond model and Burgers model can simulate the creep behavior of rock. Combining the sinusoidal disturbance function with the exponential function, a function expression for simulating the attenuation oscillation disturbance is proposed. The application of attenuation oscillation disturbance in numerical simulation is realized by Fish language, and the creep process of sandstone under attenuation oscillation disturbance is simulated. The simulation results show that compared with the undisturbed rock sample, the accelerated creep time of the rock sample under the action of attenuation oscillation disturbance is earlier and the creep deformation is larger. Before and after the disturbance is applied, the distribution of crack dip angle changes from concentration to dispersion, and the failure mode is tensile-shear composite failure mode. When the attenuation oscillation disturbance is applied, the creep deformation of rock shows a similar attenuation oscillation trend. The greater the deviatoric stress, the greater the influence of attenuation oscillation disturbance on rock deformation. The application of attenuation oscillation disturbance is more likely to lead to the fracture of contact bond between particles and accelerate energy dissipation. The attenuation oscillation disturbance element and the nonlinear viscoplastic body are introduced into the Burgers model, and an improved Burgers model is established. The theoretical curve is in good agreement with the experimental data. The model can better characterize the creep process of sandstone under attenuation oscillation disturbance.

Key words: attenuation oscillation disturbance, discrete element method, creep characteristics, Burgers model, sandstone