Research on the Instability Mechanism and Key Control Technologies of Surrounding Rock in Ultra-large Section Dense Strip Roadways

Jinchuan Shen

doi:10.54097/a45h9521

Authors

Jinchuan Shen

DOI:

https://doi.org/10.54097/a45h9521

Keywords:

Large section; Strip mining; Coal pillar protection; Surrounding rock control.

Abstract

To study the instability mechanism of the surrounding rock and the reasonable width of coal pillars in ultra-large cross-section dense strip roadways, the 7810 working face roadway in Wuyang Coal Mine was taken as the research object. Theoretical analysis, numerical simulation and on-site industrial tests were adopted to investigate the instability mechanism of the surrounding rock and the stress distribution law of the surrounding rock in ultra-large cross-section dense strip roadways. The research results show that when the width of the coal pillar between the strips is less than 5m, the vertical stress inside the coal pillar is generally small, and the stress peak is less than the initial stress; when the width of the supporting coal pillar is 5-8m, the vertical stress inside the coal pillar is greater than the initial stress, but the stress concentration is not severe, and the stress concentration coefficient is 1.05-1.49; when the width of the supporting coal pillar is between 8-12m, the peak supporting pressure appears in the center of the strip coal pillar, the overall supporting pressure inside the coal pillar is large, and the stress concentration coefficient is 1.73-2.68. The surrounding rock supporting pressure is high and it is easy to accumulate a large amount of elastic energy, which is not conducive to the long-term stability of the strip coal pillar and the safe use of the roadway. Therefore, under the existing conditions, the width of the coal pillar between the dense strip roadways is 5-8m. The research results provide a reference for the excavation and maintenance of dense strip roadways under similar geological conditions.

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