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http://dx.doi.org/10.9711/KTAJ.2021.23.2.119

Analysis of pillar stability according to reinforcement method for very near parallel tunnel  

Jo, Young-Seok (Dept. of Civil and Environmental Engineering, Dongguk University)
Kim, Yun-Hee (Dept. of Civil and Environmental Engineering, Dongguk University)
Hong, Ji-Yeon (Dept. of Civil and Environmental Engineering, Dongguk University)
Kim, Dong-Gyou (Korea Institute of Civil Engineering and Building Technology)
Kim, Bumjoo (Dept. of Civil and Environmental Engineering, Dongguk University)
Publication Information
Journal of Korean Tunnelling and Underground Space Association / v.23, no.2, 2021 , pp. 119-131 More about this Journal
Abstract
In general, the stress is concentrated on the pillar of very near parallel tunnel (VNPT), and the pillar has been reinforced by using steel-wires to maintain the stability of the tunnel. However, since the strength of the pillar decreases in the soil layer, the reinforcing pillar with the steel-wires is insufficient for tunnel stability. In this study, the laboratory tunnel experiment was conducted to examine the reinforcement effect for a new method, of which the pillar of VNPT is strengthened by using steel-pipes. As a result, against overburden stress, the bearing capacity of the steel-pipe reinforcement was 22% greater than that of the steel-wire reinforcement. In using the Particle Image Velocimetry method, the analysis shows that the steel-pipe reinforcement forms a more favorable condition of which uniformly the overburden load acts on the VNPT and the pillar than the steel-wire reinforcement. Based on the results, the steel-pipe reinforcement is expected to bring a more positive effect on tunnel stability than the steel-wire reinforcement.
Keywords
Very near parallel tunnel; Pillar; Steel-pipe reinforcement; Laboratory tunnel experiment; Particle image velocimetry;
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