| In soft rock conditions, the surrounding rock of tunnel project has a significant rheology,which brings a series of special issues to the construction process and design of supporting structure. Only from the viewpoint of rheology, instability of the tunnel during construction period, surrounding rock displacement, stress of support structures and othersdeveloping with time can be reasonably explainedbased on the stress and deformation of surrounding rock. Only by considering the relationshipbetween deformation and time-the creep effect, the nature of the interaction force changes with time between surrounding rock and supporting structure can be fully illustrated, meanwhile, it can provide some guidancefor the construction technique. Therefore, this is important to the researchof deformation features and support parameter when consideringcreep characteristicsof tunnelsurroundingrock.In this paper, the actual engineering project is hydraulic tunnel of Muliriver. By means of theoretical analysis, experimental research and numerical simulation study, the research of deformation characteristic of tunnel considering effect of surrounding rock is studied, as well as thedesign issues ofthe application timing of tunnel supporting structure. The main contents are as follows:(1) The variation pattern of convergence displacement of tunnel surrounding rock was received by use of similar model testindoor. Study the mechanics for the construction of tunnel in weak rock and the damage form of supporting structure。(2)Using the finite difference software FLAC3D considering the creep effect,mechanical characteristics of tunnel surrounding rock after excavation were analyzed.(3)By simulating different supporting opportunity and thickness of the primary support and secondary lining, variation pattern of convergence displacement and internal forces of supporting structure are obtained.From the point of controlling structure internal forces and surrounding rock displacement,the best supporting opportunity and thickness of the supporting structures are obtained considering the creep effect. |
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