The Research Of Contrast On Structure And Construction Schemes Between Double-arch Tunnel And Neighbourhood Tunnel In Expressway

At present, there is a problem with the expressway construction in our country: Double-arch tunnel and neighbourhood tunnel must be chosen in the regions with special landform and geologic condition, for the reason of route and link, space between the normal double tunnels can not satisfy the criterion. According to the double-arch tunnel in the second stage work of expressway from Zhangjiakou to Shijiazhuang, the safety of tunnel structure and the stability of surrounding rock have been appraised in the base of on-site monitoring. To compare the different structures of double-arch tunnel and neighbourhood tunnel, a FLAC computational model with complex earth's surface is established, and elastic-plastic method is used to research into the vault settlement, convergence of tunnel inner perimeter, stability of middle wall and stress state of surrounding rock. In the end, the neighbourhood tunnel is confirmed to be the best one. It is hoped that the result will be useful to the similar tunnel engineering.