Research on the Application of Double Sidewall Method in Excavation of Grade V Surrounding Rock Section of Daguanting Tunnel
In view of the problems encountered in the Daguanting tunnel using the reserved core soil method to cross the grade V surrounding rock section,this paper analyzes the characteristics of surrounding rock fragmentation and deformation failure in Daguanting tunnel.The double sidewall method is adopted in the excavation of grade V surrounding rock section of Daguanting tunnel.Compared with the reserved core soil method,after the adoption of double sidewall method for excavation,the surrounding displacement of the tunnel is reduced by about 4 mm,which is about 40%of the surrounding displacement;the vault displacement is reduced by about 3 mm,the settlement is reduced by about 35%;and the surface settlement is also greatly reduced.The results show that the double sidewall method can improve the stability efficiency of tunnel deformation and reduce the settlement of tunnel roof and ground surface.Compared with the reserved core soil method,the double sidewall method is more suitable for the working condition of grade V surrounding rock.
double sidewall methodtunnel excavationgrade V surrounding rockdeformation monitoring
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