Shang S, Yu Z L, Sun J,et al.Optimization of narrow coal pillar width and deformation and failure characteristics of gob-side entries in thick coal seams[J].Journal of Henan Polytechnic University(Natural Science) ,2026,45(6):51-61.

doi:10.16186/j.cnki.1673-9787.2024040051

Received:2024/04/25

Revised:2025/03/03

Published:2026/10/09

Optimization of narrow coal pillar width and deformation and failure characteristics of gob-side entries in thick coal seams

Shang Shuai, Yu Zhonglin, Sun Jian, Jia Hao

School of Mining Engineering， Anhui University of Science & Technology， Huainan 232001， Anhui， China

Abstract: Objectives To ensure safe mining during gob-side entry driving in thick coal seams， this study investigates the optimal coal pillar width and the deformation and failure characteristics of the surrounding rock of gob-side entries.  Methods The 9106 working face of Linfen Tianyu Hengsheng Coal Industry， a subsidiary of Wanbei Coal and Electricity Group， was selected as the engineering case. Based on a theoretical analysis indicating a reasonable coal pillar width of 7.03~12.44 m for gob-side entry driving， FLAC3D was used to simulate the distributions of stress， displacement， and plastic zones in the surrounding rock when the coal pillar widths were 8， 9， and 10 m， respectively. Three monitoring schemes were designed for roadway surrounding rock displacement， roof fracture distribution， and coal pillar stress distribution. HCZ-2 borehole stress meters， borehole imaging， and DDWJ-2 multipoint displacement meters were used to monitor the distribution of lateral abutment pressure and the failure characteristics at different positions within the coal pillar during the mining of the working face when the narrow coal pillar width was 8 m. The deformation characteristics of the surrounding rock of the gob-side entry were also analyzed.  Results The results showed that the lateral abutment pressure generally increased and then decreased from the working-face side toward the goaf side. Obvious fractures and fractured zones occurred within the 0~2.5 m and 4.6~8.0 m ranges of the coal pillar， corresponding to the plastic failure zones， whereas the coal pillar exhibited good integrity within the 2.5~4.6 m range， corresponding to the elastic zone. The maximum deformation rates of the two roadway ribs at the two monitoring points were both greater than those of the roof and floor， and the displacement in the shallow surrounding rock was significantly greater than that in the deeper surrounding rock. Conclusions The optimized section coal pillar width of 8 m can ensure the safe mining of the 9106 working face.

Key words: gob-side entry; failure characteristics; coal pillar width; abutment pressure; plastic failure zone