Effects of excavation and support schemes on stability of surrounding rock of tunnels

The impact of excavation and construction methods on the stability of tunnels with general quality rock is studied. The construction plans are developed, taking into account two factors during tunnel construction: the installation of support and the time of support installation. Based on the Hoek-Brown criteria, numerical simulations of tunnel construction plans are performed using the FLAC^3D to investigate the stability of the surrounding rock of tunnels based on the convergence constraint principle. The results indicate that the factor of whether or not support is installed has a significant impact on the shape and characteristics of the longitudinal characteristic curve of the tunnels. Under the condition of considering no support installation, the differences in the shape and characteristics of the longitudinal characteristic curve under different excavation conditions are not significant. Considering the time of support installation and whether or not support is installed does not have a significant impact on the safety factor of the surrounding rock.