Effect of Separation Between Main and Divergent Tunnels in Divergence Section of Double-Deck Tunnel on the Stability

복층터널 분기구에서의 터널 이격에 따른 안정성 영향

La, You-Sung;Kim, Bum-Joo

  • Received : 2016.03.31
  • Accepted : 2016.06.13
  • Published : 2016.06.30


Double deck tunnels are considered to have a large demand in a near future for solving traffic congestion problems and overcoming the limitations in constructing new tunnels. This study presents a numerical investigation using finite element (FE) analysis on the behaviors of the tunnels and the stability of pillars in a divergence section where single tunnel is diverged from a main line double deck tunnel. The effects of the separation distance between the diverged and the main tunnels and the ground condition were examined through the FE analysis by varying the separation distance from 0.1D to 2.0D (D: diameter of main tunnel) and the rock class from class I to V, respectively, and the analysis results were compared with those using empirical methods, strength-stress ratio, and the volume of interference. The FE analysis results indicated that the separation distance has a larger effect on tunnel behaviors, compared with the rock strength, and a single tunnel with a large cross section is more favorable than two separated tunnels for tunnel stability when the separation distance is below 0.7D.


Double-deck tunnel;Divergence;Separation Distance;Tunnel stability


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Supported by : Ministry of Land, Infrastructure and Transport of Korean government