Journal of Korean Tunnelling and Underground Space Association (한국터널지하공간학회 논문집)

Korean Tunnelling and Underground Space Association (한국터널지하공간학회)
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Utilization of induced polarization for predicting ground condition ahead of tunnel face in subsea tunnelling: laboratory test

유도분극을 활용한 해저터널 굴착면 전방 지반상태 예측: 실내실험

  • Park, Jinho (School of Civil, Environmental and Architectural Engineering, Korea University) ;
  • Lee, Kang-Hyun (Korea Expressway Corporation Research Institute, Disaster & Safety Research Division) ;
  • Lee, Seong-Won (SOC Research Institute, Korea Institute of Construction Technology) ;
  • Ryu, Young-Moo (School of Civil, Environmental and Architectural Engineering, Korea University) ;
  • Lee, In-Mo (School of Civil, Environmental and Architectural Engineering, Korea University)
  • 박진호 (고려대학교 건축사회환경공학부) ;
  • 이강현 (한국도로공사 도로교통연구원 안전연구실) ;
  • 이성원 (한국건설기술연구원 SOC 성능연구소 Geo-인프라 연구실) ;
  • 유영무 (고려대학교 건축사회환경공학부) ;
  • 이인모 (고려대학교 건축사회환경공학부)
  • Received : 2015.05.08
  • Accepted : 2015.05.20
  • Published : 2015.05.31
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Abstract

In subsea tunnelling, prediction of the fractured zone (or water bearing zone) ahead of tunnel face saturated by seawater with high water pressure has been a key factor for safe construction. This study verified the feasibility of utilizing induced polarization (IP) survey at tunnel face for predicting the ground condition ahead of the subsea tunnel face. A pore model was proposed to compute chargeability in granular material, and the relationship correlating chargeability with the variables affecting the chargeability was derived from the model. Parametric study has been performed on the variables to figure out the most influential factors affecting the chargeability. The results of the parametric study show that the size of narrow pores ($r_1$) and the salinity of pore water are the most influential factors on chargeability. Laboratory tests were conducted on various types of ground condition by changing the salinity of pore water, the thickness of the fracture zone and the existence of gouge (weathered granite) within the joints of the fractured zone to figure out the effect of the ground characteristics on the IP phenomenon. Test results show that the chargeability of the fractured zone saturated by seawater increases if the joints in the fractured zone are filled with gouge since the infilled gouge will decrease the size of narrow pores ($r_1$).

해저터널 건설 중 터널 굴착면 전방에 존재하는 고수압 조건의 함수대 (또는 포화상태의 파쇄대)의 상태를 정확히 예측하는 것은 터널 안전시공의 핵심적인 요소이다. 이 연구는 해저터널 굴착면에서 전방지반의 상태를 예측하기 위해 유도분극(Induced Polarization, IP) 탐사의 활용 가능성을 입증하였다. 모래지반에서의 충전성(chargeability)을 산정하기 위해 간극모델을 제안하고, 충전성과 이에 영향을 미치는 변수들 사이의 관계식을 유도하였다. 관계식을 사용하여 매개변수 분석을 실시하였으며 그 결과 입자 사이의 간극 중 좁은 간극($r_1$)의 크기와 간극수의 염도가 충전성에 가장 큰 영향을 미쳤다. 또한, 실내실험으로 유도분극 현상에 영향을 미치는 지반조건을 파악하기 위해 간극수의 염도와 파쇄대의 두께 변화 그리고 가우지(gouge) 존재 여부에 따른 충전성과 전기비저항의 변화 추이를 규명하고자 하였다. 그 결과 파쇄대의 절리 사이에 가우지가 충진된 경우, 해수조건에서도 충전성이 높게 나타났다. 이는 가우지가 좁은 간극($r_1$)의 크기를 감소시키기 때문이라고 판단된다.

Keywords

References

  1. Fridrikhsberg, D.A., Sidorova, M.P. (1961), "Issledovanie sviazi yav-lenia vyzvannoi polarizatsii s electrokineticheskimi svoistvami kapi-llarnyh sistem (A study of the relationship between the induced polarization phenomenon and the electrokinetic properties of cap-illary systems)", (In Russian.) Vestnik Leningradskogo Universiteta. Seria Chimia 4, pp. 222-226.
  2. Kormiltsev, V.V. (1963), "O vozbuzhdenii i spade vyzvannoi polarizatsiiv kapilliarnoi srede (On the excitation and decay of induced polarization in a capillary medium)", (In Russian) Seria Geofizicheskaya (Solid Earth Phys). Vol. 11, pp. 1658-1666.
  3. Kruyt, H.R. (1952), Colloid Science, Vol. 1. Elsevier, New York, pp. 115-193.
  4. Lee, I.M., Choi, S.S., Kim, S.T., Kim, C.K., Jun, J.S. (2002), "3D analysis of fracture zones ahead of tunnel face using seismic reflection", Tunnelling Technology, Vol. 4, No. 4, pp. 301-317.
  5. Park, Jinho, Lee, K.H., Lee, S.W., Han, E.S., Lee, I.M. (2015), "Utilization of chargeability for predicting ground condition ahead of tunnel face during subsea tunnelling", Korean Tunnelling and Underground Space Association Annual Spring Conference, pp. 179-181.
  6. Roy, K.K., Ellott, H.M. (1980), "Resistivity and IP survey for delineating saline water and fresh water zones", Geoexploration, Vol. 18, pp. 145-162. https://doi.org/10.1016/0016-7142(80)90026-5
  7. Seara, J.L., Granda, A. (1987), "Interpretation of I.P. time-time domain/resistivity sounding for delineating sea-water intrusions in some coastal areas of the northeast of Spain", Geoexploration, Vol. 24, pp. 153-167. https://doi.org/10.1016/0016-7142(87)90089-5
  8. Titov, K., Kemna, A., Tarasov, A., Vereecken, H. (2004), "Induced polarization of unsaturated sands determined through time domain measurements", Vadose Zone Journal, Vol. 3, pp. 1160-1168. https://doi.org/10.2136/vzj2004.1160
  9. Titov, K., Komarov, V., Tarasov, V., Levitski. (2002), "Theoretical and experimental study of time domain-induced polarization in water-saturated sands", Journal of Applied Geophysics, Vol. 50, pp. 417-433. https://doi.org/10.1016/S0926-9851(02)00168-4
  10. Tuller, M., Or, D., Dudley, L.M. (1999), "Adsorption and capillary condensation in porous media: liquid retention and interfacial configurations in angular pores", Water Resources Research, Vol. 35, No. 7, PP. 1949-1964. https://doi.org/10.1029/1999WR900098
  11. Wait, J.R. (1982), Geo-electromagnetism, Academic Press, San Diego, CA.

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