| Summary: | 碩士 === 國立臺灣科技大學 === 營建工程系 === 91 === The long tunnel construction are played as a key role in highway networks in Taiwan. Therefore understanding the complicated mechanisms of intersection is needed for long tunnel planning, designing and construction. The intersection research relating large underground machine cavern of traffic networks is very lack and its mechanism is unclear. This research focuses on the mechanical behaviors of intersection between ventilator tunnel and large machine cavern of eastern freeway in Taiwan. The breakage influence of the intersection to large cavern are investigated by using the three dimensional numerical code FLAC3D. At first, a numerical model of tunnel intersection was established, and Mohr-coulomb model was used. At second, the monitoring points are set on the intersection boundary, includes roof, sidewall and invert position. The variation of stress at these monitor points under construction sequential stages are analyzed in the research.
The analytic results show that compression zone occurred at the sidewall of breakage boundary. This prior support before breakage needs to endure the stress increment of breakage, such as using more shot concrete or rock bolt to carry on the extra stresses. The stress increments of maximum, intermediate, and minimum principal stresses of breakage in the studying case are 22%, 23%, and 170% respectively. These results useful at provide a reference to support’s stress design.
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