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<p>Coal pillars play a critical role in maintaining roadway stability and controlling ground pressure in underground coal mining. Under hard roof and inclined seam conditions, coal pillars are often excessively wide, resulting in significant loss of recoverable coal resources. Based on the 15,203 panel case study from Fuda Coal Mine, this research investigates mechanical properties of roof strata, analyzes hard roof fracturing behavior, and optimizes narrow coal pillar width design for gob-side entry retaining (GER). The results show that: (1) Hard roof and inclined seam increase the roof span over the coal wall and elevate the load on the coal pillar. As a result, the critical equilibrium width of the coal pillar at the 15,203 panel increases from 18.06&#xa0;m to 23.67&#xa0;m. (2) Limestone exhibits minimal deformation before reaching its yield strength, with a uniform internal stress distribution and more active microcrack initiation and propagation. Multiple cracks appear on the specimen surface upon failure, indicating that limestone does not accumulate excessive energy and can effectively support the overlying strata. (3) When the narrow coal pillar width is set to 6&#xa0;m, an elastic core forms in the central region, and the entire pillar remains in a shear-p state, which is favorable for roadway stability and is thus identified as the optimal reserved width. These findings provide a theoretical basis for the design of narrow coal pillar widths under similar complex geological conditions.</p>

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Optimized design of narrow coal pillars under hard roof and inclined seam conditions based on fracture behavior and stability analysis

  • 期刊论文

  • 发表日期：

    2025年10月13日

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  • Yang Li,
  • Xiaoming Shi,
  • Yuliang Wang,
  • Jinlong Cao,
  • Yutong Cui,
  • Nan Wang,
  • Tiezheng Li

摘要

Coal pillars play a critical role in maintaining roadway stability and controlling ground pressure in underground coal mining. Under hard roof and inclined seam conditions, coal pillars are often excessively wide, resulting in significant loss of recoverable coal resources. Based on the 15,203 panel case study from Fuda Coal Mine, this research investigates mechanical properties of roof strata, analyzes hard roof fracturing behavior, and optimizes narrow coal pillar width design for gob-side entry retaining (GER). The results show that: (1) Hard roof and inclined seam increase the roof span over the coal wall and elevate the load on the coal pillar. As a result, the critical equilibrium width of the coal pillar at the 15,203 panel increases from 18.06 m to 23.67 m. (2) Limestone exhibits minimal deformation before reaching its yield strength, with a uniform internal stress distribution and more active microcrack initiation and propagation. Multiple cracks appear on the specimen surface upon failure, indicating that limestone does not accumulate excessive energy and can effectively support the overlying strata. (3) When the narrow coal pillar width is set to 6 m, an elastic core forms in the central region, and the entire pillar remains in a shear-p state, which is favorable for roadway stability and is thus identified as the optimal reserved width. These findings provide a theoretical basis for the design of narrow coal pillar widths under similar complex geological conditions.