Study on surrounding rock failure mechanism and rational coal pillar width of the gob‐side coal roadway under influence of intense dynamic pressure

Abstract

A reasonable width of the coal pillar is very important to the surrounding rock control of the gob-side roadway. An unreasonable width of the coal pillar will make the roadway to be located within the range of strong mining influence, leading to severe deformation of the roadway. Severe subsidence at the coal pillar side of the roof and serious coal pillar deformation are problems caused by strong dynamic pressure due to mining in the gob-side coal roadway. This paper studies the surrounding rock instability mechanism and rational coal pillar width of the gob-side coal roadway under the influence of intense dynamic pressure. The results show that: (1) Under the condition of large mining height, the roadway overburden is a hinged structure, and an unreasonable coal pillar width makes the gob-side coal roadway to be located below the main roof fracture line. The rotary movement of the key block of the main roof is the main reason for the roadway deformation. (2) According to the evolution law of stress field, displacement field and plastic zone of surrounding rock of roadway under different coal pillar widths during roadway driving and mining were studied, and it is concluded that a 6-m-width coal pillar is the most reasonable. (3) Based on the stress distribution and plasticizing range of surrounding rock in a narrow pillar roadway, the combined support scheme of "anchor cable + grouting + single prop" is proposed and applied to engineering practice. The practice results show that the roadway deformation is well controlled, and the safe mining of the working face is realized.

Research on the Failure Mechanism of Surrounding Rock in a Dynamic Pressure Roadway and Active and Passive Coordinated Support Technology

“…Ma et al [15] observed that the effectiveness of U-shaped steel supports in mitigating deformation and damage to roadways under dynamic pressure was limited. Wang et al [16] studied the stress field in a side coal roadway of a goaf under the influence of mining, and they suggested a support scheme that combines "anchor cable + grouting + single pillar". Zhu et al [17] developed a mechanical model to analyze the behavior of rock beams on roadways' floors subjected to dynamic pressure, quantified the displacement when each load acted independently, and proposed a control method of "bottom crane + bottom corner anchor + floor anchor" to control roadways under dynamic pressure.…”

Stability control of goaf‐driven roadway surrounding rock under interchange remaining coal pillar in close distance coal seams

“…To improve the narrow coal pillar stability, control technologies such as rational coal pillar width, 19 roof cutting pressure relief, 20–24 and strengthened support 25 have been proposed. There are also joint applications of multiple technologies 26–28 . In addition, Chen et al 29 proposed filling the goaf to improve the narrow coal pillars stability.…”

“…There are also joint applications of multiple technologies. [26][27][28] In addition, Chen et al 29 proposed filling the goaf to improve the narrow coal pillars stability.…”

Numerical Investigation on the Yield Pillar Bearing Capacity under the Two-End-Type Cable Reinforcement

“…Their findings champion the use of high-prestressed strong anchor rods and comprehensive cable supports as effective tools in mitigating deformation in gob-side entry paths. Meanwhile, Wang et al [8] amalgamated various methodologies-from field investigations to laboratory tests, from numerical models to theoretical insights-to discern the inconsistent deformation mechanisms in slim coal pillar pathways. Their research indicates that maintaining a 6 m breadth for coal pillars optimizes outcomes.…”