Abstract:
TBMs had been successfully applied in the excavation of deep-buried roadways in coal mines due to its good construction safety and fast tunneling speed. TBMs are able to safely and efficiently excavated roadways for gas and water hazard controlling in coal mines, and alleviates the problem of misalignment in coal mine excavation. In order to improve the flexibility of TBMs used in deep-buried coal mines and expand the application range of TBMs in deep coal mine roadway excavation, the design principles and technical indicators of coal mine miniature TBMs are proposed, including the size and weight of the whole machine and components, the explosion-proof, formation adaptability, and solutions that need to be met of coal mine micro TBMs. The configurations and main parameters of the coal mine micro TBM were determined, and the coal mine micro TBM was designed and manufactured. The technical difficulties and solutions in the research as well as development of coal mine micro-TBM and construction technology are systematically demonstrated. According to the engineering geological conditions of gas drainage roadway in coal mine micro-TBM tunneling, numerical analysis of surrounding rock stability of micro TBM exvated coal mine roadway under different support conditions is carried out. Based on the numerical analysis results, comprehensively considering the support effect and support efficiency, the roadway support scheme is optimized, and the in-situ monitoring of the deformation of the roadway surrounding rock and the axial force of the rokbolts are implemented. The monitoring results show that, within 20 days after the roadway excavation, the deformation of the surrounding rock and the axial force of the rockbolt increase rapidly. About 65 days after the excavation, the deformation of the surrounding rock tends to stop, and the axial forces of the rockbolts also stopped increasing. The axial forces of the rockbolts which are installed on the roadway roof are slightly larger than those of installed on the shoulder and sides. The overall stability of the surrounding rock of the roadway is good, which can meet the requirements of subsequent gas control projects. Excavating coal mine gas drainage roadways by using micro TBMs, the efficiency of roadway supporting meets the requirements of penetration rates of micro TBM. The average heading speed reached up to 300 m/mth, the highest heading speed are 15 m/shift and 41.6 m/d. the heading speed of micro TBM 3~6 times of drilling and blasting.