| Summary: | 碩士 === 國立中興大學 === 土木工程學系所 === 102 === Open tunnel is commonly used in the road in which up-slope is inherent in loose condition and susceptible collapse to assure the safety of road travelling. The design of open tunnel with limited width will come with the road constraint or not play of open tunnel. If the structure of open tunnel can be designed as outer hang type, the road will be increased to the normal width to meet the objective of complete road use. In this study, the Plaxis 2D numerical program is used to analyze the real example of open tunnel with limited road width. From the analyzed results, it is indicated: 1. The outer hang type of open tunnel is adopted to increase the road width. In this way, the internal great forces in some regions such as bottom slab, outer column, top beam and inner side wall will be induced. The structure design should be carefully considered. 2. If the colluvial soil above the open tunnel can be suitably reduced, the global forces in open tunnel structure will be relatively mitigated. 3. The large displacement is found in the colluvial soil above the open tunnel. This is due to the load of backsoil and colluvial soil itself. The
displacement in the lower part of down-slope cannot be ignored. 4. The adequate information through complete engineering analysis of open tunnel with limited road width can provide references in the design of
related engineering projects.
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