Deformation characteristics and failure evolution in deep high-stress roadways under creep action

Abstract

As geotechnical engineering continues to expand into deep underground environments, it is common for creep effects to cause large deformations of roadways and damage to supporting structures. For this purpose, a large-scale model experiment is conducted with a 1300 m deep roadway as the engineering background. Creep-similar materials for prototype rock and construction specifications, as well as designed supporting components and work processes, were developed. Pressure-preserved loading is applied for physical models. The results indicate that the sequence of roadway failure is “floor-heave induced roadway-foot deformation → roadway-foot levered sidewall-bulge → sidewall-bulge driven roof-sink → full-section convergence”. The strain of the roadway changes from compressive to tensile, and it fails when the ultimate tensile strain is reached. The surrounding rock within 0.2 times the width of the roadway is extremely fractured and stripped. Multiple intersecting fissures are visible near the roadway and extend from the surface to the deep interior. The integrity reduction coefficient of the surrounding rock in the original support anchorage zone is greater than 80%, and the rockbolts along with the surrounding rock are deformed toward the center of the roadway. The numerical simulation and field test can verify the authenticity of the model experiments. Finally, the countermeasures of “ floor protection and sidewall control” and “surface-shallow-deep” triple-bearing structures are proposed. The research results can guide the control of creep deformations in deep high-stress roadways.