Creep Characteristics Of Deep Roadway Under Hydro-Mechanical Conditions And Its Control Mechanisms

The seepage flow of underground water is one important factor which causes failure and severely large rheological deformation of deep roadway. So researching the creep characteristics of deep roadway under hydro-mechanical conditions and its control mechanisms has theoretical and engineering significance to solve a lot of control problems with the surrounding rock of deep water-enriched roadway. The article taking the geological conditions of deep water-enriched roadway engineering as the research background, comprehensively using laboratory experiments, theoretical analysis, numerical simulation and field monitoring, to deeply and systematically study on the creep characteristics of deep roadway under hydro-mechanical conditions and its control mechanisms, which has gained below innovative achievements:(1) Creep-seepage coupled experiments have systematically been launched by using self-developed rock seepage device and matching with MTS816 rock electro-hydraulic servo test system, and the evolution of creep deformation, flow rate, coefficient of permeability along with time have been obtained under different post-peak stresses, confining pressures and pore pressures. And the creep properties and permeability characteristics of post-peak rock have been revealed under hydro-mechanical conditions. Creep damage forms and micro fracture mechanism of rock have been ascertained by CT scanning and SEM.(2) Based on the results of the creep-seepage coupled experiments with post-peak rock, introducing nonlinear viscoplastic body to improve Nishihara model, so the nonlinear creep model of post-peak rock has been established under hydro-mechanical conditions. The three-dimensional constitutive equation of nonlinear creep model of post-peak rock has been deduced by Laplace integral transform, and the creep parameters identification of the model by the nonlinear optimization algorithm Quasi-Newton. Combining with the fluid-solid coupling theory, the nonlinear creep-seepage coupled model has been established which can been implanted into FLAC 3D that can simulate the axial compression process of rock under hydro-mechanical conditions. The simulation results are in good agreement with the experimental results that proves the validity and reliability of the model.(3) Based on the geological conditions of typical deep water-enriched roadway engineering and post-peak nonlinear creep-seepage model of rock that previously proposed, three-dimensional numerical model of deep roadway under coupled hydraulic and mechanical loading was established. Stress, displacement, the plastic zone distribution and hydro evolution of deep roadway surrounding rocks considering hydraulic were researched systematically. What’s more, creep, failure and hydro variation under different pore water pressure and time and other factors were analysed. Finally, creep and failure mechanism of deep roadway surrounding rocks under coupled hydraulic and mechanical loading was revealed.(4) Against the large deformations with rheological characteristics of surrounding rocks in deep water-enriched roadway, the “yield-bolt grouting” coupled control method has been raised which taking high pressure yield grouting-bolt as the core. Systematically researching the different yield ranges, yield pressures and grouting time on the influence of stress, deformation and plastic distribution of deep roadway under hydro-mechanical conditions, and revealing the control mechanism of the large deformation in deep water-enriched roadway by the ‘yield-bolt grouting’ coupled support which providing a new technical way to solve the control problem with water-enriched roadway.