Abstract:
As coal mining progressively reaches the deeper strata,the substantial deformation and rheological properties of mine roadways have become one of the most challenging issues to supporting systems.In order to investigate the aging characteristics of damage and dete-rioration of the rock surrounding deep mine roadways and develop dynamic reinforcement technologies, a comprehensive study ncorporating laboratory experiments, theoretical analysis, numerical simulation and field testing was conducted.The findings include: (1) An analytical solution for the deformation pattern of circular, axisymmetric roadways was derived using the Laplace inverse transformation.Via a combination of theoretical analysis, equivalent transformation for non-circular roadways and field tests, the radius of the plastic zone was determined to be between 1.5 and 2.1 m, which in turn leads to an analytical solution for the aging deformation of the surrounding rock for straight-wall semicircular arch roadways.(2) Based on models of elastic and elastoplastic roadways, energy dissipation was employed to characterize the aging properties of surrounding rock damage and deterioration and the evolution trend of the plastic zone, determining an optimal timing for the primary support.(3) The evolutionary trend of timeliness damage and deterioration of the surrounding rock after primary support was obtained.Based on the peak ratio of vertical stress, a secondary support scheme and its timing have been determined.The shear stress, vertical stress and the range of the plastic zone in the surrounding rock were further analyzed, determining the length of secondary support bolts to be 3.0 m and setting the support timing to be between 40 and 70 days.The research outcomes provide a theoretical foundation and practical guidance for the design and maintenance of roadways in deep coal mines.