DOI QR코드

DOI QR Code

A comparative study on the stability evaluation of double deck tunnel in terms of excavation

대심도 복층터널에 대한 굴착 안정성 평가 비교 연구

  • Jang, Namju (Geotechnical Department, Sambo Engineering Co., Ltd.) ;
  • Gang, Han-gil (Geotechnical Department, Sambo Engineering Co., Ltd.) ;
  • Kim, Kihwan (Geotechnical Department, Sambo Engineering Co., Ltd.) ;
  • Choi, Chang-rim (Geotechnical Department, Sambo Engineering Co., Ltd.)
  • 장남주 (삼보기술단 지반사업부) ;
  • 강한길 (삼보기술단 지반사업부) ;
  • 김기환 (삼보기술단 지반사업부) ;
  • 최창림 (삼보기술단 지반사업부)
  • Received : 2018.12.01
  • Accepted : 2018.12.14
  • Published : 2019.01.31

Abstract

It is necessary to construct underground in the metropolis. Road traffic has reached saturation point. The city has several underground road construction projects. In abroad, double deck tunnels are planned and constructed. It is attained a high level of underground development technology. In case the double deck tunnel (2 lane) is planed instead of the bidirectional tunnel (2 lane), excavation area is similar. But tunnel width is decreased. The reduced width can cut cost for the tunnel reinforcement. This study evaluates the stability of excavation on double deck tunnel. By the assessment of the strength-stress ratio and strength reduction method, quantitative analysis is conducted between double deck tunnel and the bidirectional tunnel.

TNTNB3_2019_v21n1_155_f0001.png 이미지

Fig. 1. Calculation of local factor of safety (You et al., 2000)

TNTNB3_2019_v21n1_155_f0002.png 이미지

Fig. 2. Shear strength and trial shear strength (Park and You, 1998)

TNTNB3_2019_v21n1_155_f0003.png 이미지

Fig. 3. Road alignment plan in branch section (Seoul ○○○ tunnel)

TNTNB3_2019_v21n1_155_f0004.png 이미지

Fig. 4. Road alignment plan in branch section– reduced speed section (up), raised speed section (down)

Table 1. Tunnel in branch section (Seoul ○○○ tunnel)

TNTNB3_2019_v21n1_155_t0001.png 이미지

Table 2. Double deck tunnel in branch section

TNTNB3_2019_v21n1_155_t0002.png 이미지

Table 3. Analysis condition

TNTNB3_2019_v21n1_155_t0003.png 이미지

Table 4. Properties of rock mass

TNTNB3_2019_v21n1_155_t0004.png 이미지

Table 5. Load relaxation factors

TNTNB3_2019_v21n1_155_t0005.png 이미지

Table 6. Rock support pattern

TNTNB3_2019_v21n1_155_t0006.png 이미지

Table 7. Plastic failure zone in single tunnel

TNTNB3_2019_v21n1_155_t0007.png 이미지

Table 8. Plastic failure zone in double deck tunnel

TNTNB3_2019_v21n1_155_t0008.png 이미지

Table 9. Local factor of safety in single tunnel and double deck tunnel

TNTNB3_2019_v21n1_155_t0009.png 이미지

Table 10. Global factor of safety in single tunnel and double deck tunnel

TNTNB3_2019_v21n1_155_t0010.png 이미지

Acknowledgement

Grant : 대심도 복층터널 설계기술 및 시공기술개발

Supported by : 국토교통과학기술진흥원

References

  1. Duncan, J.M. (1996), "State of the art: limit equilibrium and finite-element analysis of slopes", Journal of Geotechnical Engineering, Vol. 122, No. 7, pp. 577-596. https://doi.org/10.1061/(ASCE)0733-9410(1996)122:7(577)
  2. Nam, K.M., Choi, M.K., Kim, J.J., Yoo, H.K. (2017), "Stability analysis of an existing utility tunnel due to the excavation of a divergence tunnel emerging from double-deck tunnel", Journal of Korean Tunnelling and Underground Space Association, Vol. 19, No. 2, pp. 231-248. https://doi.org/10.9711/KTAJ.2017.19.2.231
  3. Park, J.W., Park, Y.J., You, K.H., Lee, S.D. (2004), "A study on the assessment of safety factor tunnels", Journal of Korea Society for Rock Mechanics, Vol. 14, No. 5, pp. 327-338.
  4. Park, Y.J., Chae, Y.S., You, K.H., Paik, Y.S. (1999), "Slope stability analysis by slice method and finite difference method -A comparative study-", Journal of Korean Geotechnical Society, Vol. 15, No. 6, pp. 263-272.
  5. Park, Y.J., You, K.H. (1998), "Stability analysis for jointed rock slope using ubiquitous joint model", Journal of the Korean Society for Rock Mechanics, Vol. 8, No. 4, pp. 287-295.
  6. You, K.H., Park, Y.J., Bae, G.J. (2000), "An assessment of safety factor for tunnels excavated in a weak rock layer", Journal of Korean Tunnelling and Underground Space Association, Vol. 2, No. 3, pp. 47-57.