Tunnel Boring Machine (TBM) has been introduced into coal mine rock tunneling construction because of its good safety, fast driving speed and high mechanization degree. The geological conditions of coal mine are complex, and the influence of composite strata on the efficiency of full-section rock TBM cannot be ignored. In order to investigate the effect of coal measure composite formation on the rock breaking efficiency of the hob, the particle flow discrete unit model of the hob and rock was established, and the numerical experiment of the penetration of TBM hob was carried out. The results show that the damage range of composite strata is small under the same rock breaking condition, and it is not easy to form through zone during the process of hob rock breaking. The number of cracks in the two formations varies with the penetration degree roughly in the same way. Under the same rock breaking condition, the normal force of hob required by composite formation is greater than that required by single formation hard rock. The optimum penetration of rock breaking by single formation hob is about 4 mm, and the optimum penetration of rock breaking by composite formation hob is about 9 mm.
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