Equivalent creep damage modeling and large deformation of soft rock under complex stresses

Soft rock roadways are prone to subject to creep damage under long-term loading, infuencing their stability. This study investigated the mechanical and creep characteristics of the soft surrounding rock in field and laboratory. A nonlinear creep damage model was developed and validated using UDEC numerical simulations. The time-dependent deformation behavior was examined, and an optimized support scheme, involving lengthened pre-stressed anchor, was proposed and implemented to the field. The results show that creep rate and deformation increase with stress, prolonging the steady-state creep transition. The accelerated creep curve from simulations aligns with experimental results, confirming the model's reliability. The creep-induced deformation and expanding fissures reveal deficiencies in the original support system. The optimized scheme improves the cooperative control and stability of the support system.