Stability analysis of surrounding rock in novel mining-induced self-forming roadway without advance tunnelling

Abstract

The mining-induced self-forming roadway without advance tunnelling (MSRWAT) method is an innovative longwall mining technique developed in China. In this method, the roadway is formed automatically by the coal shearer during coal extraction, eliminating the need for chain pillars and all advance roadway excavation. This study investigates the stability of MSRWAT roadway, with a particular focus on its unique formation mechanism. The results show that the average convergence between the roof and floor in MSRWAT roadway is 11.34% lower than in gob-side entry retaining by roof cutting (GERBRC) roadway, primarily because the MSRWAT roadway avoids the abutment stress ahead of the mining face. Compared to conventional rectangular roadways, the cambered side of the MSRWAT roadways reduce failure depth by 5% to 40% across different conditions. This cambered geometry optimizes the stress distribution, minimizing the development of tensile stress in the surrounding rock. Based on these findings, corresponding engineering recommendations were proposed and successfully validated in the field. Field monitoring shows that the surrounding rock deformation in MSRWAT roadway is 73.67% less than that in GERBRC roadway. This work confirms the superior stability of MSRWAT roadways and offers practical guidance for implementing no pillar mining technology in underground coal mines.

Keywords

Gob-side entry retaining / Roadway stability / Roof cutting / Automatically formed roadway / No pillar mining

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