Determination of coal pillar width for gob‐side entry driving in isolated coal face and its control in deep soft‐broken coal seam: A case study

Abstract

Large deformation control of surrounding rock in deep soft-broken coal roadway has always been a key scientific and technological problem restricting the deep coal resources exploitation. Taking the gob-side entry driving (GED) in isolated coal face under deep soft-broken coal as research object, the prominent difficulties of surrounding rock control were clarified. Through numerical simulation, the evolution laws of deviatoric stress and plastic zone of GED under different coal pillar widths were studied. Combined with rational calculation, reasonable coal pillar width was determined to be 7.0 m. The study shows that severe disturbance distance in the front section of the coal face is 22 m, and makes it clear that coal pillar and roof are the key control areas. A subregional asymmetric combined support technology named anchor cable truss in roof and coal pillar + anchor cable in solid coal + single prop reinforced support in 25 m ahead of the coal face was proposed. The field application and ground pressure observation results show that good control effect has been achieved after adopting subregional asymmetric support technology under 7 m coal pillar width. The research results have important reference significance for safe mining in deep coal resources.

Stability analysis and control technology of gob-side entry retaining with double roadways by filling with high-water material in gently inclined coal seam

“…The peak distances on the solid coal side and mining side are 2.48 and 2.91 m, respectively. The surrounding rock in the shallow roof is in a failure state with a low stress value (Kang 2021;Liu et al 2020;Wang and Xie 2022;Xie et al 2022), which is the key control area of surrounding rock of the roadway. Before the mining disturbance of 2202 working face, the plastic zone ranges of the roadway roof, solid coal side, and mining side are 2.94 m, 2.48 m, and 2.83 m, respectively, which are the same as the vertical stress distribution of the roadway approximately.…”

Mining‐induced failure characteristics and surrounding rock control of gob‐side entry driving adjacent to filling working face in the deep coal mine

“…A reasonable coal pillar width plays a crucial role not only in controlling surface subsidence but also in surrounding rock control. 34,35 When the adjacent working face is backfilled, the factors influencing the width of the coal pillar mainly regard the stress and plastic zone of the GED.…”

Investigation on rational width of coal pillar and roadway support in isolated panel of extra-thick coal seam

“…By analyzing overall process of coal pillar deformation and failure, Wagner obtained that the existence of elastic zone is conducive to maintaining the stability of yield pillar. By exploring the evolution characteristics of deviatoric stress in deep large deformation surrounding rock, Wang et al (Wang and Xie, 2022) proposed to use anchor cable truss for horizontal and vertical displacement control. Yang et al (Yang et al, 2017) used shotcrete and bolt to control the roadway failure through simulating the law of crack propagation in the roadway under supported and unsupported conditions.…”