Failure Mechanism for Surrounding Rock of Deep Circular Roadway in Coal Mine Based on Mining‐Induced Plastic Zone

Abstract

In order to reveal the failure mechanism of the deep roadway under mining-induced pressure in coal mine, the boundary equations for the plastic zone around the deep roadway were deduced, and then the evolution laws for morphology of the plastic zone and the relationship between the morphological indexes and the stability of surrounding rock were discussed. The results show that, for the deep roadway, the effect of mining on the plastic zone is more sensitive than that on the shallow one. Even if the changes of mining influence are small, they may also cause extremely serious plastic failure of surrounding rock masses, leading to the sudden instability of the roadway. When the plastic wings of the plastic zone are approximately perpendicular to the roof, floor, or sidewall, the large deformation and failure of the deep roadway are very likely to occur. Compared with the index of the uniformity coefficient, the irregular shape coefficient can be used to better characterize the differences in the plastic zone morphology. Finally, a case study was provided to apply the principles for the formation and extension of a butterfly-shaped plastic zone.

Stability of a Roadway below a Coal Seam under Dynamic Pressure: A Case Study of the 11123 Floor Gas Drainage Roadway of a Mine in Huainan, China

“…It is difficult to effectively capture the information in this stage by conventional testing methods (pressure gauge, displacement gauge, borehole TV, etc.) [5,42]. e comprehensive monitoring technology adopted in this study can capture the change information of physical and chemical fields of rock mass at macro-and microlevels [8,12,29,30,34,38].…”

“…e transfer of mining stress to the floor rock mass will eventually lead to the deformation and destruction of rock strata within a certain depth of the floor. At that time, if the floor gas drainage roadway is located in the affected area and the on-site support conditions are insufficient, this will inevitably lead to the instability of the surrounding rock and of the floor gas drainage roadway and even render the operation of the roadway equipment system unsafe [3][4][5].…”

Influence of Three-Dimensional Stress Field Variation on Fracture Evolution Characteristics of a Roof

“…The entry roof tends to fail and become more instable with the increase in mining intensity and mining depths [3]. The failure and instability of the roof result from the formation of the fracture zone in the surrounding rock mass of the entry [4,5]. It is of great significance in the aspects of theoretical analysis and field applications to understand the fracture pattern and its evolution in the surrounding rock mass of the roof in order to maintain the stability of the roof and prevent dynamic disasters [6].…”

Study on Presplitting Blasting the Roof Strata of Adjacent Roadway to Control Roadway Deformation

“…A protective coal pillar of 10∼30 m should be left between adjacent working faces to prevent the roadway from deformation and damage in traditional long wall mining [1][2][3]. As the depth of mining continues to increase, the surrounding rock of the roadway gradually exhibits the characteristics of soft rock under the influence of high ground stress, high ground temperature, high osmotic pressure, and strong mining disturbance [4][5][6][7]. e velocity and time of creep are greater than those of shallow rock strata [8,9].…”