Stability Analysis of Surrounding Rock in Portal Section of Plateau Loose Rock Pile Tunnel Under Different Construction Methods

Rock pile is a rock block formed by weathering of bedrock, and its stability is lower than that of other rock and soil. Therefore, there are numerous difficulties in the construction of tunnels through rock pile. In this paper, TBM method, three step method and CD method are chosen as the basis of tunnel stability analysis, and the numerical model of surrounding rock excavation stability of tunnel passing through rock pile is established. In this paper, the tunnel excavation is simulated by numerical simulation software, and the stability analysis of tunnel under different construction methods is performed. Combined with the engineering background and calculation analysis, compared with the three construction methods, it is found that the CD method has the strongest comprehensive protection for tunnel construction and is a more suitable construction method for crossing the rock pile tunnel.