Abstract:
The surrounding rock of deep roadways often exhibits significant fragmentation and swelling creep characteristics during failure, making anchor mesh and shotcrete support ineffective. This leads to continuous large deformations of the surrounding rock or widespread damage to the roadway, severely affecting the safe and efficient production of mines. The control of swelling creep in fractured surrounding rock of deep roadways has become a prominent technical challenge restricting the safe development of deep mineral resources. To investigate the creep mechanism of anchor bodies in fractured surrounding rock and the long-term effectiveness of anchor bolts, a nonlinear viscous component is introduced to represent the nonlinear creep stage of deep fractured surrounding rock based on the classic Burgers creep model and fracture degree variable. A nonlinear creep constitutive model for the anchor body in deep fractured surrounding rock is established by combining the elastic component representation of anchor bolts in parallel. Parameter identification for the creep constitutive model of deep fractured surrounding rock cubic samples is conducted using strain-time curves under the final stress stage. FLAC
3D is used to simulate and analyze the long-term stability of deep fractured surrounding rock roadways, producing deformation-support time characteristic curves. The interaction between the surrounding rock and anchor bolts under different anchor bolt lengths and spacing is analyzed, effectively proving that the deformation of deep roadway surrounding rock is time-effect. Moreover, anchor bolts, anchor cables, and other support measures can effectively limit the creep deformation of surrounding rock. The study also reveals the impact of burial depth (stress level) and lateral pressure coefficient (stress state) on the deformation of deep fractured surrounding rock roadways and the long-term force on anchor bolts. The findings identify the applicable working conditions for anchor bolts in deep roadways and indicate that anchor support has its own adaptability. The results provide a theoretical basis for solving the long-term control problems of fractured surrounding rock in deep roadways and have important theoretical and engineering application value for the safe development of deep mineral resources.