Supporting and controlling rock deformation mechanism of pipe roof in Dawangding shallow tunnel

Pipe roof advance support technology in the shallow tunnels construction has been used widely in preventing tunnel collapse, controlling surrounding rock deformation. Currently, the computational theory about pipe roof supporting effect is still not perfect; design procedures also did not make clear regulation. Based on Dawangding tunnel engineering, citing elastic foundation model, the stress characteristics in different construction stages of pipe roofs and surrounding rock were analyzed, and the effect which pipe roofs limit rock deformation was researched by using numerical simulation, through displacement and stress curves, research shows that pipe roof supporting function mainly reflects in controlling rock initial deformation, adjusting stress distribution of surrounding rock, uniforming vaults settlement The both sides of the arch feet deformation in tunnel construction should be closely monitored to prevent local damage.