Spatial Effect Analysis On Construction Of Dual-Arch Tunnel

The thesis is based on the comprehensive analysis of current dual-arch tunnel research results. Combined with the key technology research on the Dual-arch Tunnel in the western region by Ministry of Communications. This thesis aims to solve the problems of spatial effect and supported occasion in process of dual-arch tunnel construction. Deep-embedded and shallow-embedded dual-arch tunnels with sixteen works are separately simulated by three-dimensional numerical method. Program of finite difference method FLAC3D is applied to study stress characteristics, supporting opportunity and spatial effect of dual-arch tunnel in the condition of complicated construction procedures.By 3-D finite element analysis of dual-arch tunnel, it draws the conclusion on the following factors : basic stress law , stress performance and applicable condition of each kind of midboard reasonable construction technology, reasonable spacing interval between working face . reasonable clearing between the pignon and lining structure changing regulation and controlling basis of rim displacement proper opportunity of temporary lining striking and blasting vibration to secondary lining and midboard of each kind of work condition in every geologic and tolography condition. It puts forward reasonable construction technology supporting mode and supporting ageing under the different geology condition .well discloses stress characteristic , supporting opportunity and spatial effect of dual-arch tunnel in the condition of complicated construction procedures. The results show that stress of dual-arch tunnel relates not only with construction technology rigidity and strength of support structure, but also with supporting occasion and spatial effect etc. The results also show that the stress of dual-arch tunnel is controlled by supporting opportunity and spatial effect in the condition of complicated construction procedures. These results should be of guiding significance to design and construct dual-arch tunnel engineering.