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

Korean Tunnelling and Underground Space Association (한국터널지하공간학회)
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Analysis of grout injection distance in single rock joint

단일절리 암반에서 그라우팅 주입거리 분석

  • Ji-Yeong Kim (Dept. of Civil & Environmental Engineering, Pusan National University) ;
  • Jo-Hyun Weon (Dept. of Civil & Environmental Engineering, Pusan National University) ;
  • Jong-Won Lee (Research Institute of Industrial Technology, Pusan National University) ;
  • Tae-Min Oh (Dept. of Civil & Environmental Engineering, Pusan National University)
  • 김지영 (부산대학교 사회환경시스템공학과) ;
  • 원조현 (부산대학교 사회환경시스템공학과) ;
  • 이종원 (부산대학교 생산기술연구소) ;
  • 오태민 (부산대학교 사회환경시스템공학과)
  • Received : 2023.10.30
  • Accepted : 2023.11.14
  • Published : 2023.11.30
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Abstract

The utilization of underground spaces in relation to tunnels and energy/waste storage is on the rise. To ensure the stability of underground spaces, it is crucial to reinforce rock fractures and discontinuities. Discontinuities, such as joints, can weaken the strength of the rock and lead to groundwater inflow into underground spaces. In order to enhance the strength and stability of the area around these discontinuities, rock grouting techniques are employed. However, during rock grouting, it is impossible to visually confirm whether the grouting material is being smoothly injected as intended. Without proper injection, the expected increases in strength, durability, and degree of consolidation may not be achieved. Therefore, it is necessary to predict in advance whether the grouting material is being injected as designed. In this study, we aimed to assess the injection performance based on injection variables such as the water/cement mixture ratio, injection pressure, and injection flow using UDEC (Universal Distinct Element Code) numerical program. Additionally, numerical results were validated by the lab experiment. The results of this study are expected to help optimize variables such as injection material properties, injection time, and pump pressure in the grouting design in the field.

터널 및 에너지/폐기물 저장과 관련하여 지하공간의 활용이 증가하는 추세이다. 지하공간의 안정성 확보를 위해서는 암반균열 및 절리를 보강하는 것이 중요하다. 절리와 같은 불연속면은 암반의 강도를 저하시키고, 지하공간 내부로 지하수 유입을 발생시킬 수 있다. 불연속면 주변의 암반 강도의 증대와 차수를 위해 암반 그라우팅을 활용할 수 있다. 그러나 암반 그라우팅 시 주입재료가 암반 절리 내 원활하게 주입되고 있는지 직접적인 확인에 한계가 있다. 그라우팅 주입재가 사전에 목표한 설계안과 같이 주입되지 않을 시 강도, 내구성 증대 및 차수성 향상 효과를 볼 수 없다. 따라서 실험적으로 평가가 어려운 그라우팅 주입재가 설계대로 주입되고 있는지 수치해석을 활용하여 사전에 평가할 필요가 있다. 본 연구에서는 개별요소 수치해석 프로그램인 UDEC (Universal Distinct Element Code)을 활용한 그라우팅 주입재의 물/시멘트 배합비, 주입압력, 주입유량과 같은 주입변수에 따른 주입성능을 평가하였다. 또한 실내실험을 통해 수치해석 결과와 비교하여 수치해석 모델의 신뢰도를 검증하였다. 본 연구결과는 향후 현장에서 그라우팅 설계 시 주입재의 물성, 주입시간, 펌프 압력과 같은 변수들을 최적화할 수 있는데 도움이 될 것으로 기대된다.

Keywords

Acknowledgement

본 연구는 한국연구재단(지역대학우수과학자지원사업)의 지원(No. NRF-2022R1I1A3065299)을 받아 수행된 연구입니다.

References

  1. Baek, S.H., Joo, H.W., Kwon, T.H., Han, J.T., Lee, J.H., Yoo, W.K. (2020), "Effect of permeability anisotropy on the effective radius of grout bulb in horizontal permeation grouting - numerical study", Journal of the Korean Geotechnical Society, Vol. 36, No. 11, pp. 149-156. https://doi.org/10.7843/KGS.2020.36.11.149
  2. Bandis, S.C., Lumsden, A.C., Barton, N.R. (1983), "Fundamentals of rock joint deformation", International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts, Vol. 20, No. 6, pp. 249-268.
  3. Barton, N., Choubey, V. (1977), "The shear strength of rock joints in theory and practice", Rock mechanics, Vol. 10, pp. 1-54. https://doi.org/10.1007/BF01261801
  4. Barton, N., Lien, R., Lunde, J.J.R.M. (1974), "Engineering classification of rock masses for the design of tunnel support", Rock mechanics, Vol. 6, pp. 189-236. https://doi.org/10.1007/BF01239496
  5. Choi, S.O., Chung, S.K. (2004), "Stability analysis of jointed rock slopes with the Barton-Bandis constitutive model in UDEC", International Journal of Rock Mechanics and Mining Sciences, Vol. 41, No. 3, pp. 581-586. https://doi.org/10.1016/j.ijrmms.2004.03.103
  6. Hong, S.Y., Kwon, S.H., Min, K.B., Ji, S.H. (2021), "Effect of excavation and thermal stress on slip zone and aperture change around disposal hole and tunnel in fractured rock", Tunnel and Underground Space, Vol. 31, No. 2, pp. 125-144. https://doi.org/10.7474/TUS.2021.31.2.125
  7. Jeon, K.H., Ryu, D.W., Kim, H.M., Park, E.S., Song, J.J. (2010), "Numerical analysis of grout flow and injection pressure affected by joint roughness and aperture", Tunnel and Underground Space, Vol. 20, No. 2, pp. 82-91.
  8. Kim, J.H., Choi, B.I. (2018), "Mechanical and microstructural analysis of cement suspension", Magazine of the Korea Concrete Institute, Vol. 30, No. 3, pp. 33-37.
  9. Kim, J.M., Lee, E.K. (2022), "A fundamental study on the criteria of basic parameters for planning rock grouting", Journal of the Korean Geotechnical Society, Vol. 38, No. 2, pp. 15-27. https://doi.org/10.7843/kgs.2012.28.2.15
  10. Kim, S.H., Kim, T.K., Choi, J.I., Yim, K.W. (2010), "A study on the injection efficiency and strength for grouting method", Journal of the Korean Geotechnical Society, Vol. 26, No. 9, pp. 47-58. https://doi.org/10.7843/kgs.2011.27.9.047
  11. Koh, H.S., Cho, B.J. (2021), "Performance evaluation of injection grouting method for structure foundation ground improvement", Journal of Disaster and Safety, Vol. 3, No. 1, pp. 1-10.
  12. Lee, J.W., Kim, H.M., Yazdani, M., Park, E.S. (2017), "Influence of design parameters of grout injection in rock mass using numerical analysis", Tunnel and Underground Space, Vol. 27, No. 5, pp. 324-332. https://doi.org/10.7474/TUS.2017.27.5.324
  13. Lee, J.W., Kim, J.Y., Weon, J.H., Oh, T.M. (2022), "Time-dependent characteristics of viscous fluid for rock grouting", Journal of Korean Tunnelling and Underground Space Association, Vol. 24, No. 6, pp. 465-481. https://doi.org/10.9711/KTAJ.2022.24.6.465
  14. Lee, W.H., Lim, H.D. (2007), "Analysis of fine particle transfer and shear strength increase using PFC in permeation grouting", Journal of the Korean Geotechnical Society, Vol. 23, No. 11, pp. 49-58. https://doi.org/10.7843/KGS.2007.23.11.49
  15. Nam, H.Y., Lee, W.J., Lee, C.H., Choo, H.W. (2018), "Estimation of unconfined compressive strength (UCS) of microfine cement grouted sand", Journal of the Korean Geotechnical Society, Vol. 34, No. 7, pp. 5-15. https://doi.org/10.7843/KGS.2018.34.7.5
  16. Oh, J.Y., Park, H.K., Chang, S.B., Choi, H.S. (2018), "Numerical investigation on the effect of backfill grouting on ground behavior during shield TBM tunneling in sandy ground", Journal of Korean Tunnelling and Underground Space Association, Vol. 20, No. 2, pp. 375-392.
  17. Park, J.H., Park, Y.W. (2003), "Investigation of the optimum injection pressure in pressure grouting by laboratory model tests", Journal of the Korean Geotechnical Society, Vol. 19, No. 2, pp. 217-225.
  18. Park, J.W., Park, C.H., Lee, C.S. (2021), "Hydro-mechanical modeling of fracture opening and slip using grain-based distinct element model: DECOVALEX-2023 Task G (Benchmark Simulation)", Tunnel and Underground Space, Vol. 31, No. 4, pp. 270-288.
  19. Saeidi, O., Ramezanzadeh, A., Sereshki, F., Jalali, M.E. (2013a), "Numerical modeling of the effects of joint hydraulic aperture, orientation and spacing on rock grouting using UDEC: a case study of Bakhtiary Dam of Iran", Journal of Mining and Environment, Vol. 4, No. 1, pp. 15-26.
  20. Saeidi, O., Stille, H., Torabi, S.R. (2013b), "Numerical and analytical analyses of the effects of different joint and grout properties on the rock mass groutability", Tunnelling and Underground Space Technology, Vol. 38, pp. 11-25. https://doi.org/10.1016/j.tust.2013.05.005
  21. Yoon, I.K., Moon, J.H., Lee, J.S., Kim, Y.K. (2021), "Characteristics of high-viscosity grouting materials for rock joint reinforcement of deep tunnel", Journal of the Korean Geo-Environmental Society, Vol. 22, No. 12, pp. 59-63. https://doi.org/10.14481/JKGES.2021.22.12.59