Time-dependent behavior of deep roadway surrounding rock considering damage induced by excavation and mining disturbances: Experiments, modeling, and simulation

In deep coal mining, surrounding rock is subjected to both high in-situ stress and intense mining disturbances, leading to significant time-dependent behavior. Accurately capturing this behavior is essential for predicting long-term roadway stability, necessitating the development of a reliable constitutive creep model and numerical simulation approach. In this study, creep experiments were conducted on pre-damaged rock with varying initial damage levels to investigate the time-dependent mechanical properties. Based on the experimental results, an accelerated-creep criterion was proposed, and an elastic-viscoplastic creep damage model (EVPCD) was established that simultaneously considers the effects of time-dependent damage and instantaneous damage caused by stress disturbances on rock creep behavior. Subsequently, the effectiveness of the proposed creep model was verified using experimental data, and the secondary development of the EVPCD model was completed based on the FLAC3D platform. Following this, a long-term stability analysis method of deep surrounding rock that accounts for excavation-and mining-induced disturbances was proposed. Using the main roadway of Xutuan Coal Mine as a case study, numerical simulations were carried out to investigate the time-dependent deformation and failure characteristics of the surrounding rock following excavation and mining disturbance. Combined with on-site monitoring of the surrounding rock damage areas, the results indicate that the EVPCD outperforms the CVISC and Nishihara models in predicting the time-dependent behavior of deep surrounding rock.