Prediction of Rock Mass Strength Ahead of Tunnel Face Using Hydraulic Drilling Data

천공데이터를 이용한 터널 굴진면 전방 암반강도 예측

  • 김광염 (한국건설기술연구원 기반시설연구본부) ;
  • 김성권 (한국건설기술연구원 기반시설연구본부) ;
  • 김창용 (한국건설기술연구원 기반시설연구본부) ;
  • 김광식 (한국건설기술연구원 기반시설연구본부)
  • Published : 2009.12.31

Abstract

Appropriate investigation of ground condition near excavation face in tunnelling is an inevitable process for safe and economical construction. In this study mechanical parameters from drilling process for blasting were investigated for the purpose of predicting the ground condition, especially rock mass strength, ahead of tunnel face. Rock mass strength is one of the most important factors for classification of rock mass and making a decision of support type in underground construction. Several rock specimens which are considered homogeneous and having different strength values respectively were tested by hydraulic drill machines generally used. As a result, penetration rate is fairly related with rock mass strength among drilling parameters. It is also found that penetration rate increases along with the higher impact pressure even under same rock strength condition. It is finally suggested that new prediction method for rock mass strength using percussive pressure and penetration rate during drilling work can be utilized well in construction site.

터널 굴착시 굴진면 전방의 지반상태를 사전에 파악하는 것은 터널의 안정성을 증가시킴과 동시에 시공성을 향상시켜 경제적인 터널 시공을 할 수 있도록 한다. 이에 본 연구에서는 터널 천공시 획득되는 천공데이터를 이용하여 굴진면 전방의 암반강도를 예측하고자 하였다. 이는 암반강도가 현장에서 암반분류 및 지보패턴 설계 등의 핵심인자로 가장 보편적으로 활용될 뿐만 아니라, 암반강도의 변화를 통해 굴진면 전방의 지반상태 변화를 예측하는데도 활용할 수 있기 때문이다. 이를 위해 본 연구에서는 다양한 강도 특성을 보이는 균질한 암석시험편을 대상으로 착암기 종류를 변화시켜가며 천공실험을 수행하였다. 실험결과 천공속도는 다른 천공데이터들과 착암기의 종류 및 암석의 강도에 따라 고유한 값을 보이는 것으로 나타났다. 또한, 동일한 암석에 대해 천공시 타격압이 증가하면 천공속도는 선형적으로 비례하여 증가하는 것으로 나타났다. 이러한 결과를 바탕으로 본 연구에서는 터널 시공 현장에서 착암기의 제원, 현장 계측 데이터 및 천공속도와 암반강도의 상관관계를 이용하여 터널 굴진면 전방의 암반강도를 예측할 수 있는 방안을 제안하였다.

Keywords

References

  1. 김광염, 김창용, 김광식, 2008, 균질암반에서의 유압식 천공데이터 평가, 한국암반공학회, Vol. 16, No. 6, pp. 480-490
  2. 김광염, 김창용, 임성빈, 윤현석, 서용석, 2006, 국내 터널시공 중 막장지질조사의 문제점 및 개선방안에 관한 연구, 대한지질공학회, Vol. 16, No. 3, pp. 265-273
  3. 김낙영, 김성환, 정형식, 2001, 도로터널에서 지보패턴별 굴착지수 상관관계 고찰, 한국터널공학회 터널기술논문집, Vol. 3, No. 14, pp. 17-24
  4. 한국도로공사, 1992, 도로설계요령, 제 4권 터널편
  5. Farmer IW, Garritly P., 1987, Prediction of roadheader cutting performance from fracture toughness considerations. In: Herget G, Vongpaisal S, editors. Proceedings of the Sixth International Congr Rock Mechanics, pp. 621-624
  6. Howarth DF, Adamson WR, Berndt JR., 1986, Correlation of model tunnel boring and drilling machine performances with rock properties. Int J Rock Mech Min Sci, 23, pp. 171–175
  7. Hughes H., 1972, Some aspects of rock machining. Int J Rock Mech Min Sci, 9, pp. 205-211 https://doi.org/10.1016/0148-9062(72)90023-X
  8. Kahraman S., 1999, Rotary and percussive drilling prediction using regression analysis. Int J Rock Mech Min Sci, 36, pp. 981-989 https://doi.org/10.1016/S0148-9062(99)00050-9
  9. Mellor M., 1972, Normalization of specific energy values. Int J Rock Mech Min Sci, 9, pp. 661-663 https://doi.org/10.1016/0148-9062(72)90016-2
  10. Mituisumitomo corporation, 2005, Tunnel rock mass evaluation that uses Drill-Logging system, Proceedings of the 60th Symposium, Japan Society of Civil Engineers, pp. 9-10
  11. Paone J, Madson D, Bruce WE., 1969, Drillability studieslaboratory percussive drilling. USBM RI 7300
  12. Pathinkar AG, Misra GB., 1976, A critical appraisal of the protodyakonov index. Int J Rock Mech Min Sci, 13, pp. 249-251 https://doi.org/10.1016/0148-9062(76)91545-X
  13. Pool D., 1987, The effectiveness of tunnelling machines. Tunn Tunnel, pp. 66–67
  14. Protodyakonov MM., 1962, Mechanical properties and drillability of rocks. In: Proceedings of the Fifth Symposium on Rock Mechanics. Minneapolis, MN: University of Minnesota, pp. 103–118
  15. Rabia H, Brook N., 1980, An empirical equation for drill performance prediction. The state of the arts in rock mechanics. In: Proceedings of the 21st US Symposium on Rock Mechanics. Columbia, MO: University of Missouri-Rolla, pp. 103-111
  16. Rabia H, Brook N., 1981, The effects of apparatus size and surface area of charge on the impact strength of rock. Int J Rock Mech Min Sci, 18, pp.211-219 https://doi.org/10.1016/0148-9062(81)90975-X
  17. Rabia H., 1982, Specific energy as a criterion for drilling performance prediction. Int J Rock Mech Min Sci, 19, pp. 39-42
  18. Rabia H., 1985, A unified prediction model for percussive and rotary drilling. Min Sci Technol, 2, pp. 207-216 https://doi.org/10.1016/S0167-9031(85)90149-5
  19. Schmidt RL., 1972, Drillability studies-Percussive drilling in the field. USBM RI 7684
  20. Selim AA, Bruce WE., 1970, Prediction of penetration rate for percussive drilling. USBM RI 7396
  21. Selmer-Olsen R, Blindheim OT., 1970 On the drillability of rock by percussive drilling. In: Proceedings of the Second Congress International Society on Rock Mechanics, pp. 65-70
  22. Sinkala T., 1991, Improving hole quality by automatic control of the drilling process: theoretical and field studies. Min Sci Technol, 12, pp. 79-88 https://doi.org/10.1016/0167-9031(91)91561-U
  23. Tandanand S, Unger HF., 1975, Drillability determination-A drillability index of percussive drills. USBM RI 8073
  24. Teale R., 1965, The concept of specific energy in rock drilling. Int J Rock Mech Min Sci , 2, pp. 57-71 https://doi.org/10.1016/0148-9062(65)90022-7
  25. Thuro K, Spaun G., 1996, Introducing the 'destruction work' as a new rock property of toughness referring to drillability in conventional drill and blast tunnelling. In: Barla M, editor. Eurock'96 Prediction and Performance in Rock Mechanics and Rock Engineering, vol. 2, pp. 707-713
  26. Toda corporation, 2005, Prediction of Geological condition forward of tunnel face with drilling data, Proceedings of the 60th Symposium, Japan Society of Civil Engineers, pp. 13-14