Highway Tunnel Portal Form Classification And Its Applicable Condition Research

In order to highway tunnel portal form classification and applicable conditions are studied, using thenetwork investigation and field survey methods at home and abroad, collected a total of more than400tunnel portal images and related data, and the analysis of data collation, preparation of tunnel portalinformation management database, at the same time through consulting massive literature materials andusing database the inquiry function to the collected data were analyzed, the function and role of tunnelportal, portal forms the classification, characteristics and applicable conditions are studied, the mainconclusions and results are as follows：(1) Through network investigation and field survey that tunnel portal construction at the mostunfavourable situation for complex in broken surrounding rock of portal section of shallow buried, lining,bias and by excavation induced landslide, tunnel surrounding rock gradeⅣ,Ⅴmainly to surrounding rock;tunnel portal for most applications for end wall tunnel portal and cut bamboo portal.(2) According to the relational model of knowledge representation,use the Microsft SQL Server2000design the tunnel portal information management database. Tunnel portal information managementdatabase content is rich, information content is big, covers the entrance original landforms, constructionprocess, construction problems and solutions, as well as the design drawings and a lot of valuable video,audio and text information. There are information Can be provided as a sample for the design andconstruction of tunnel portal, as well as portal evaluation and construction reference provides a basis, forthe design and construction of reference application.(3) Based on the AHP and used The three level control standard, by considering the action of stressand form factor, this paper proposed a new classification of tunnel portal. This new classification dividedtunnel portal into "force" and "unforce" in two categories. On this basis, based on a large amount of actualengineering example analysis, summarizes various portal form characteristics, and puts forward theapplicable conditions, for the majority of the design staff to provide reference.(4) In this paper, using finite element analysis software ANSYSY on cutting type portal structure wascarried out in three numerical simulation, studies the stress characteristics of cutting portal, the shadingjunction for cutting portal design focus, the largest settlement in tunnel lighting at the junction of the archtop and there exists stress mutation, and tensile stress force, and the maximum tensile stress in the dark atthe junction of the arch waist position, according to the different lining thickness of tunnel portal structuredisplacement and stress condition for further analysis, this paper suggest to use the50cm as a portal in thecutting thickness, in order to reduce the cost of construction.