Open Access

ARTICLE

Research on Coal Pillar Width in Roadway Driving Along Goaf Based on The Stability of Key Block

Zhengzheng Cao¹, Yuejin Zhou^1,2

1 State Key Laboratory for Geomechanics & Deep Underground Engineering, School of Mechanics & Civil Engineering, China University of Mining & Technology, Xuzhou 221116, China
2 Corresponding author: Zhou Yuejin. Tel: +86-13914884696. Email: yuejinzh@163.com

Computers, Materials & Continua 2015, 48(2), 77-90. https://doi.org/10.3970/cmc.2015.048.077

Abstract

Reasonable width design of narrow coal pillar is the key for ensuring stability of surrounding rock in the roadway driving along next goaf. Based on movement characteristics of overlying strata in gob-side entry, the paper establishes the mechanical model of surrounding rock structure for roadway driving along next goaf, and analyzes the interaction mechanism between key blocks and coal pillar. Besides, in allusion to the mechanical equilibrium of key block B in basic roof, the stability coefficients K₁ and K₂ of key block B and sensitive coefficient of influencing factor are introduced. When the stability coefficient K₁ is larger than 1, rotation instability occurs; while the stability coefficient K₂ is larger than 1, slip instability occurs. According to the stability analysis of key block B, the width design of coal pillar in roadway driving along goaf is obtained. By taking No.3307 working face in Xinan coal mine in Shandong Province as project background, the paper determines reasonable width of coal pillar, calculates stability coefficients of key blocks, and obtains sensitive coefficients of influencing factors on the stability of key blocks. The practical results indicate that the stability of key block in roadway driving along next goaf can be guaranteed when the width of coal narrow is 5.0 m. The results can provide theoretical basis and technical guidance for engineering application with similar mining conditions.

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