In this paper, the large deformation mechanism of deep dynamic pressure roadway is studied from the perspective of the formation and development of plastic zone, and creep and damage of rock mass. The results show that (a) the butterfly‐shaped plastic zone is a nonstable plastic zone, and its unique stress sensitivity and rock formation difference are important causes of disasters such as large deformation of deep roadway. (b) Established a creep model of anchored surrounding rock. Due to the existence of rock mass damage and creep, the range of the plastic zone of the surrounding rock is always dynamic. (c) Explain the mechanism of large deformation of surrounding rock in deep roadway. The source of large deformation of deep dynamic roadway lies in the formation of unstable plastic duct‐shaped zone, and the interference of external factors such as tectonic stress and mining disturbance is the main way to change the plastic zone from stable to unsteady. In addition, the increase in rock mass damage and creep promotes the continuous development of the plastic zone, which eventually leads to the large deformation of the surrounding rock of the roadway. (d) Guided by the deformation mechanism of the surrounding rock in the deep dynamic pressure roadway, the corresponding roadway support technology was proposed for the test roadway, and the better support effect was obtained through the test.

In order to clarify the influence of anchor bolts on the supporting effect of the layered weak roof and surrounding rock of nonlayered roof with good integrity, the mechanical model of the roadway with nonlayered homogeneous roof and layered weak roof was established using FLAC3D. The distribution characteristics of the stress field and the displacement field of the bolt support are analyzed, and the supporting effect of the bolt on the roof of two types of roadways is studied. The research results show that when the original rock stress is not considered, the bolt support shows obvious tensile, compressive stress areas and positive and negative displacement areas in the surrounding rock of the roof of the roadway; when the original rock stress is taken into account, the tensile and compressive stress zones and the positive and negative displacement zones of the anchor support in the surrounding rock of the roof plate disappear obviously. The effect of the bolt support on the stress field and plastic area of the surrounding rock of the two types of roadway roof is not obvious. However, it has a significant effect on suppressing discontinuous deformation such as delamination and sliding between layered roof rocks. The delamination phenomenon between rock layers disappeared obviously, and the range of each numerical curve of the displacement field of the surrounding rock in the anchoring area was significantly reduced. However, the effect of the anchor support on continuous deformation control such as elastoplastic deformation of roof rock of nonlayered roadway is very limited. There is almost no change in the displacement field curve in the depth of the roof‐surrounding rock. Only the shallow surrounding rock displacement field curve range has decreased.

Rocks surrounding deep, high-stress roadways typically undergo a vicious cycle of destruction → repair → re-destruction → re-repair over a long time. This article uses the roadway restoration project of Pingmei Mine No. 6 (400 m underground) as research object. Starting from the plastic area, the characteristics of the distribution of rock surrounding the circular roadway are analyzed, and the influence of the side pressure coefficient, cohesive force, inside friction angle, support strength, and roadway radius on the plastic area is studied. Four types of distribution patterns were observed in rocks surrounding the plastic area of the roadway: round, oval, rounded rectangle, and butterfly. The side pressure coefficient, cohesive force, and inside friction angle affected the distribution and range of rocks surrounding the plastic area of the roadway. The support radius of the roadway and the support strength of its face did not change the distribution of the plastic area, but only affected its size. Therefore, to maintain the long-term stability of weak and broken roadways, the strength of the surrounding rocks must be increased, and roadway renovation should be avoided as it affects the distribution of the plastic area and reduces its scope. Engineering practice has shown that the “anchor net spray + hollow grouting anchor cable” technology for the combined, step-by-step repair and support of roadways, with a hollow grouting anchor cable as core, can suppress the distribution and scope of the plastic area to guarantee safe and long-term use of the roadway.

To study the weakening process, deformation, and failure characteristics of rock masses surrounding deep chambers under complex stress environments, triaxial loading tests along with triaxial loading/unloading followed by uniaxial loading tests were conducted on sandstone specimens. The internal microcracks of the specimens under the loading and unloading of triaxial confining pressure were observed by scanning electron microscopy. The results revealed the inherent mechanism of plastic deformation (irreversible deformation) of the rock mass under different confining pressures. Under uniaxial loading and triaxial loading, the sandstone specimens exhibited X-shaped shear failure and single shear failure, respectively. In contrast, the sandstone samples subjected to the loading and unloading of triaxial confining pressure followed by uniaxial loading showed multiple shear fracture surfaces and fine fissures along the axial direction. A larger initial axial pressure of the sandstone specimen corresponded to a smaller uniaxial loading strength after unloading the confining pressure, a greater amount of plastic deformation, more macro- and microfissures, and more severe damage to the specimen. These results show that the final failure mode, strength, degree of damage, and plastic deformation of sandstone specimens are related to the stress state at the time of failure along with the loading history before failure.

This paper considers the 333 return airway of the Gaokeng Coal Mine to analyze the deformation characteristics and failure mechanism of the surrounding rock of the composite roof for a loose and weak coal roadway. The reasons for the large deformation are explored and the superiority of the prestressed truss and anchor rope is compared to ordinary anchor cables from the perspective of mechanics to propose a targeted coal roadway support method. Sinking of the composite roof in the coal roadway is accompanied with a release and transfer of the surrounding rock stress. The pressure of the composite roof transfers to the roadway sides and intensifies the fracture process of the coal body. As a result, the ability to support the composite roof is weakened, and it further bends and sinks to form a vicious cycle that repeats itself. Therefore, the support of the composite roof in the coal roadway should consider the roof, roadway sides, and floor as a single unit to achieve the support goal of reinforcing the roadway sides and roof. Based on the above analysis, a comprehensive control technology with a truss and anchor rope is proposed as the main body and a bolt + anchor cable + metal network as the auxiliary. This technology can improve the integral bearing capacity of the composite roof, strengthen the roadway side structures, and reinforce the roadway sides and roof. Numerical simulation and field application results show that the support scheme can effectively realize safe control of the composite roof in coal roadways.