Mechanisms Of Time-dependent Deformation Of Highly Stressed Soft-rock Roadways

In deep mining environment, roadway surrounding rock body typically exhibit significant high pressure, large deformation, long time continuous rheological properties, brought severe challenges to the deep roadway supporting and maintenance problems. To study the aging deformation mechanism of the surrounding rock in deep high stress soft rock, is very important for ensuring the long-term stability of surrounding rock in deep tunnel.. In this paper, the integrated use of theoretical analysis, the combination of numerical simulation and field monitoring method, in-depth study of the deep high stress soft rock roadway of aging processes of deformation and instability mechanism, main research results are as follows:(1) Based on classical rheological mechanics and plastic mechanics theory, established a by burgers rheological model and the linear strain softening model in series of soft rock viscoelasto plastic strain softening creep model, and derives the corresponding 3D creep constitutive equation. Compared with the conventional creep model, the model can well characterize the accelerating creep of soft rock in the third stage.(2) Based on the Cvisc creep model of FLAC3 D, the creep model of soft rock visco elastic plastic strain softening is developed for two times.. Using custom developed soft rock viscoelasto plastic strain softening creep process, established the soft rock triaxial compression creep test of numerical calculation model, the analysis of soft Yanfeng strain softening characteristic and creep deformation, numerical simulation results and the experimental results are basically consistent, and the result shows that the establishment of soft rock viscoelasto plastic strain softening model is effective.(3) Based on custom development of soft rock viscoelasto plastic strain softening creep analysis program, FLAC3 D is established in deep high stress soft rock roadway three-dimensional numerical calculation model, in-depth study of the different stress environment of soft rock roadway surrounding rock deformation, stress, plastic zone etc. along with the time evolution, reveals the deep high stress soft rock roadway of aging processes of deformation and instability mechanism.(4) To 1000 m level in a mine roadway detailed engineering geological condition as the background, using custom developed viscoelasto plastic strain softening creep analysis program, studied the roadway in the original support scheme of bolt stress variation and deformation of surrounding rock and surrounding rock plastic zone extension with time variation, and the aging of the roadway surrounding rock deformation and failure characteristics, proposed on bolt grouting for the coupling of the core support system, effectively control intense flow in the surrounding rock of roadway, to ensure the long-term stability of the surrounding rock of roadway.