The Journal of Engineering Geology (지질공학)

The Korean Society of Engineering Geology (대한지질공학회)
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Analyzing the Change of Surface Water and Groundwater Systems Caused by Tunnel Construction in Northern Ulsan City

울산시 북구 지역 터널 굴착에 의한 지표수계 및 지하수계 변화 분석

  • Jeon, Hang-Tak (Department of Geological Sciences, Pusan National University) ;
  • Hamm, Se-Yeong (Department of Geological Sciences, Pusan National University) ;
  • Lee, Chung-Mo (Department of Geological Sciences, Pusan National University) ;
  • Lim, Woo-Ri (Department of Geological Sciences, Pusan National University) ;
  • Yun, Sul-Min (Department of Geological Sciences, Pusan National University) ;
  • Park, Heung-Jai (Department of Environmental Engineering, Inje University)
  • 전항탁 (부산대학교 지질환경과학과) ;
  • 함세영 (부산대학교 지질환경과학과) ;
  • 이충모 (부산대학교 지질환경과학과) ;
  • 임우리 (부산대학교 지질환경과학과) ;
  • 윤설민 (부산대학교 지질환경과학과) ;
  • 박흥재 (인제대학교 환경공학과)
  • Received : 2018.02.26
  • Accepted : 2018.03.20
  • Published : 2018.03.31
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Abstract

Excessive groundwater discharge by tunneling and tunnel operation can lead to groundwater exhaustion and ground subsidence. Therefore, it is very important to evaluate environmental impact and to establish mitigation measures of the impact related to tunnel excavation based on hydrogeological and modeling approaches. This study examined the depletion of surface reservoirs and valley water due to tunnel excavation through field survey, water quality analysis, tracer test, and groundwater modeling. As a result of field water quality test, the concentration of chemical constituents in groundwater discharge into the tunnel is slightly higher than that of valley water. By the result of laboratory water analysis, both valley water and the groundwater belong to $Ca^{2+}+HCO_3{^-}$ type. Tracer test that was conducted between the valley at the injection point and the tunnel, indicates valley water infiltration into the ground and flowing out to the tunnel, with maximum electrical conductance changes of $70{\mu}S/cm$ in the first test and of $40{\mu}S/cm$ in the second test. By groundwater modeling, the groundwater discharge rate into the tunnel during tunnel construction is estimated as $4,942m^3/day$ and groundwater level recovers in 3 years from the tunnel completion. As a result of particle tracking modeling, the nearest particle reaches the tunnel after 6 hours and the farthest particle reaches the tunnel after 9 hours, similarly to the case of the field trace test.

터널 굴착에 의한 다량의 지하수 배출 그리고 터널 굴착 작업은 지하수 고갈과 지반침하를 유발한다. 그러므로, 수리지질학적 방법 및 모델링에 의해서 터널 굴착과 관련하여 환경 영향을 평가하고 영향 저감대책을 수립하는 것이 매우 중요하다. 이 연구는 야외조사, 수질분석, 추적자시험 그리고 지하수 모델링을 통하여 터널 굴착에 의한 저수지와 계곡수의 고갈을 밝히기 위한 것이다. 현장 수질분석 결과, 터널내 배출 지하수의 화학성분의 농도는 계곡수의 화학성분의 농도보다 약간 더 높다. 실내 수질분석 결과, 계곡수와 배출 지하수의 수질형은 둘 다 $Ca^{2+}+HCO_3{^-}$형이다. 계곡의 주입지점과 터널 간의 1차 및 2차 추적자시험에 의하면 계곡수가 지하로 침투하여 터널로 배출되며, 전기전도도는 1차시험에서는 $70{\mu}S/cm$ 그리고 2차 시험에서는 $40{\mu}S/cm$로 나타났다. 지하수 모델링에 의하면, 터널 굴착 시 터널내로의 지하수 배출량은 $4,942m^3$/일이며, 터널 완공 후 3년이 경과하면 지하수위는 원래 상태로 회복되는 것으로 산정된다. 입자추적 모델링에 의하면, 터널에 가장 가까운 입자는 주입 후 6시간 만에 그리고 가장 먼 입자는 9시간만에 터널에 도달하는 것으로 산정되었으며, 이 결과는 야외 추적자시험 결과와 비슷하다.

Keywords

References

  1. Appelo, C.A.J., Postma, D., 2007, Geochemistry, groundwater and pollution(2nd ed.), A.A. Balkema, Rotterdam.
  2. Cheong, J.-Y., Hamm, S.-Y., Yu, I.-R., Whang, H.-S., Kim S.-H., Kim, M.-S., 2015, Analysis of groundwater discharge into the Geumjeong tunnel and baseflow using groundwater modeling and long-term monitoring, Journal of Environmental Science International, 24(12), 1691-1703. https://doi.org/10.5322/JESI.2015.24.12.1691
  3. Chiocchini, U., Castaldi, F., 2011, The impact of groundwater on the excavation of tunnels in two different hydrogeological settings in central Italy, Hydrogeology Journal, 19(3), 651-669. https://doi.org/10.1007/s10040-010-0702-1
  4. Choi, M.-J., Lee, J.-Y., Koo, M.-H., Lee, K.-K., 2004, A comparative study on groundwater flow depending on conceptual models in tunnel modeling, The Journal of Engineering Geology, 14(2), 223-233.
  5. Chough, S.K., Sohn, Y.K., 2010, Tectonic and sedimentary evolution of a Cretaceous continental arcbackarc system in the Korean peninsula: New view, Earth-Science Reviews, 101(3-4), 225-249. https://doi.org/10.1016/j.earscirev.2010.05.004
  6. Chung, S.Y., Kim, B.W., Kang, D.H., Shim, B.O., Cheong, S.W., 2007, Analyses of Hydrology and Groundwater Level Fluctuation in Granite Aquifer with Tunnel Excavation, The Journal of Engineering Geology, 17(4), 635-645.
  7. Jeong, Y.-M., Gwon, Y.-J., Lee C., Lee, S.-D., Park, J.-Y., 2011, Examples of Tunnel Construction in a Large Scale Fault Zone, Magazine of Korean Tunnelling and Underground Space Association, 13(5), 76-92.
  8. Kim, B.-W., Chung, S.-Y., Cho, B.-W., Kang, D.-H., 2011, A Study on Groundwater Flow with the Characteristics of Spatial Aquifer Distribution and Faults development at Ulsan Metropolitan City, Journal of the Geological Society of Korea, 47(1), 59-71.
  9. Koh, B.-R., Choi, Y.-Y., Ko, S.-H., 2006, Characteristics of groundwater movement variation according to establishment of underground tunnel, Journal of Korean Society of Water Science and Technology, 14(4), 59-68.
  10. Korea Meteorological Administration, Retrieved from www.weather.go.kr
  11. K-water, 2004, Groundwater survey report for Ulsan.
  12. Lee, B.D., Choo, C.O., Lee, B.J., Cho, B.W., Hamm, S.-Y., Im, H.C., 2003, Numerical Modeling on the Prediction of Groundwater Recovery in the Youngchun Area, Kyungbook Province. Economic and Environmental Geology, 36(6), 431-440.
  13. Lee, B.D., Hamm, S.-Y., Lee, C.O., Cho, B.W., Sung, I.H., 2001, Relation of groundwater flow rate and fracture system associated with waterway tunnel excavation, The Journal of Engineering Geology, 11(3), 327-337.
  14. Lee, C.-M., Hamm, S.-Y., Hyun, S.G., Cheong, J.-Y., Wei, M.L., 2017, Reviewing the applications of three countries' ground water flow modeling regulatory guidelines to nuclear facilities in Korea, Journal of Soil and Groundwater Environment, 22(3), 1-9. https://doi.org/10.7857/JSGE.2017.22.3.001
  15. Lee, G.-B., Hong, G.S., Kim, G.-S., 2009, Tunnel Design by Considering on Geo - environment and Groundwater Condition, Yooshin Technical Letter, Yooshin Co.
  16. Lee, J.-H., Lee, D.-B., Kim, K.-S., Lee, S.-J., and Choi, S.-R., 2014, Reinforcement of tunnel fault zone, Journal of the Korean Geotechnical Society, 30(3), 22-32.
  17. Li, S., Li, S., Zhang, Q., Xue, Y., Liu, B., Su, M., Wang, Z., 2010, Predicting geological hazards during tunnel construction, Journal of Rock Mechanics and Geotechnical Engineering, 2(30), 232-242. https://doi.org/10.3724/SP.J.1235.2010.00232
  18. McDonald, M.G., Harbaugh, A.W., 1988, A Modular Three-Dimensional Finite-Difference Groundwater flow model: Techniques of Water-Resources Investigations of the United States Geological Survey, Book 6.
  19. Moon, J., Fernandez, G., 2010, Effect of excavation-induced groundwater level drawdown on tunnel inflow in a jointed rock mass, Engineering Geology, 110(3-4), 33-42. https://doi.org/10.1016/j.enggeo.2009.09.002
  20. Park, Y.D., Yoon, H.D., 1968, Explanatory Text and the Geological Map of Ulsan Sheet: Geological Survey of Korea.
  21. Reilly, T.E., 2001. System and Boundary Conceptualization in Ground-water Flow Simulation, Techniques of Water-Resources Investigations of the United States Geological Survey. Book 3. Applications of Hydraulics Chapter B8.
  22. Rural Groundwater net, Retrieved from www.groundwater.or.kr.
  23. Son, M., Song, C. W., Kim, M.-C., Cheon, Y.B., Jung, S.H., Cho, H.S., Kim, H.-G., 2013, Miocene crustal deformation, basin development, and tectonic implication in the southeastern Korean Peninsula, Journal of the Geological Society of Korea, 49(1), 93-118.