DOI QR코드

DOI QR Code

Effect of RMR and rock type on tunnel drilling speed

RMR과 암석종류가 터널 천공속도에 미치는 영향

  • Kim, Hae-Mahn (Dept. of Civil, Environmental, and Architectural Engineering, Korea University) ;
  • Lee, In-Mo (Dept. of Civil, Environmental, and Architectural Engineering, Korea University) ;
  • Hong, Chang-Ho (Dept. of Civil and Environmental Engineering, KAIST)
  • 김해만 (고려대학교 건축사회환경공학부) ;
  • 이인모 (고려대학교 건축사회환경공학부) ;
  • 홍창호 (한국과학기술원 건설및환경공학과)
  • Received : 2019.05.22
  • Accepted : 2019.06.21
  • Published : 2019.07.31

Abstract

Drilling and charging of the blast holes during NATM tunneling works take more than 30% of construction time among the whole tunneling work process. Prediction of ground condition ahead of tunnel face has been studied by several researchers by correlating percussion pressure and drilling speed during tunneling work with the ground condition and/or RMR values. However, most of the previous researches were conducted in the granite rock condition which is the most representative igneous rock in the Korean peninsula. In this study, drilling speeds in igneous rocks were analyzed and compared with those in sedimentary rocks (most dominantly composed of conglomerates, sandstones, and shales) under the similar RMR ranges; it was identified that the drilling speed is pretty much affected by rock types even in a similar RMR range. Under the similar RMR values, the drilling speed was faster in sedimentary rocks compared with that in igneous rock. Moreover, while the drilling speed was not much affected by change of the RMR values in igneous rocks, it became faster in sedimentary rocks as the RMR values got lower.

NATM 공법을 이용한 터널굴착 시 발파공 천공 및 장약 작업은 전체 터널 굴착 시간의 30% 이상을 차지하는 중요한 과정이다. 최근에는 이 공정을 활용하여 천공작업 도중 얻어지는 타격압, 천공속도 등을 바탕으로 터널 굴착면 전방의 지반상태, RMR 등을 예측하는 연구들이 진행되어 왔다. 하지만 선행 연구들은 대부분 화강암으로 대표되는 화성암질 지반에 대해서만 수행되어 왔다. 본 연구에서는 유사한 RMR의 범위를 가지는 화성암의 천공속도를 퇴적암(특히, 역암, 사암 및 셰일)의 천공속도와 비교/분석하였으며, 유사한 RMR 값을 가지는 암이라 하더라도 암질 종류에 따라서 천공속도가 크게 달라질 수 있음을 확인하였다. 퇴적암에서의 천공속도가 화성암에서의 속도보다 더 빨랐으며, 또한 화성암의 경우 천공속도와 RMR등급에 따른 천공속도의 차이는 거의 없는 것에 반하여, 퇴적암의 경우는 RMR등급이 낮아질수록 천공속도는 증가함을 알 수 있었다.

Keywords

TNTNB3_2019_v21n4_561_f0001.png 이미지

Fig. 1. Jumbo drill utilized in this study

TNTNB3_2019_v21n4_561_f0002.png 이미지

Fig. 2. Test sites

TNTNB3_2019_v21n4_561_f0003.png 이미지

Fig. 3. Sectional view of the tunnels and measured sections

TNTNB3_2019_v21n4_561_f0004.png 이미지

Fig. 4. Acquisition of average drilling speed (underground manager)

TNTNB3_2019_v21n4_561_f0005.png 이미지

Fig. 5. Drilling process

TNTNB3_2019_v21n4_561_f0006.png 이미지

Fig. 6. Drilling speed with different RMR

TNTNB3_2019_v21n4_561_f0007.png 이미지

Fig. 7. Drilling speed with different types of rock and RMR class

TNTNB3_2019_v21n4_561_f0008.png 이미지

Fig. 8. Sandstone near the tunnel site B

TNTNB3_2019_v21n4_561_f0009.png 이미지

Fig. 9. Relationship between RMR and drilling speed

Table 1. Specification of jumbo drill (Atlas Copco XL3C & COP 2238)

TNTNB3_2019_v21n4_561_t0001.png 이미지

Table 2. Summarization of the obtained data

TNTNB3_2019_v21n4_561_t0002.png 이미지

References

  1. Bilgin, N., Demircin, M.A., Copur, H., Balci, C., Tuncdemir, H., Akcin, N. (2006), "Dominant rock properties affecting the performance of conical picks and the comparison of some experimental and theoretical results", International Journal of Rock Mechanics and Mining Sciences, Vol. 43, No. 1, pp. 139-156. https://doi.org/10.1016/j.ijrmms.2005.04.009
  2. Jeong, H.Y., Jeon, S.W. (2018), "Linear cutting machine test for assessment of the cutting performance of a pick cutter in sedimentary rocks", Journal of Korean Tunnelling and Underground Space Association, Vol. 20, No. 1, pp. 161-182. https://doi.org/10.9711/KTAJ.2018.20.1.161
  3. Kim, K.S., Kim, J.H., Jeong, L.C., Lee, I.M., Cho, G.C. (2015), "Development for prediction system of TBM tunnel face ahead using probe drilling equipment and drilled hole imaging equipment.", Journal of Korean Tunnelling and Underground Space Association, Vol. 17, No. 3, pp. 393-401. https://doi.org/10.9711/KTAJ.2015.17.3.393
  4. Kim, K.Y., Kim, S.K, Kim, C.Y., Kim, K.S. (2009a), "Prediction of rock mass strength ahead of tunnel face using hydraulic drilling data", Tunnel and Underground Space, Vol. 19, No. 6, pp. 479-489.
  5. Kim, N.Y., Kim, S.H., Chung, H.S. (2001), "Correlation between drilling parameter and tunnel support pattern using jumbo drill", Journal of Korean Tunnelling and Underground Space Association, Vol. 3, No. 4, pp. 17-24.
  6. Kim, S.W., Choi, E.K., Lee, K.H. (2009b), "Classification of rocks in the Cenozoic unconsolidated sediments and evaluation of aggregates", Proceedings of the GSK Conference 19-30th, October, Jeju, pp. 82.
  7. Kim, Y., Kim, H.M., Lee, S.S. (2019), "An analysis of excavation cycle time for Korean tunnels and the comparison with the standard of construction estimate", Journal of Korean Tunnelling and Underground Space Association, Vol. 21, No. 1, pp. 137-153. https://doi.org/10.9711/KTAJ.2019.21.1.137
  8. Kwon, K.B., Song, C.H., Yun, J.S., Hwang, U.K. (2013), "Market and technical trend of rock drilling machine", Journal of Drive and Control, Vol. 10, No. 3, pp. 36-40.
  9. MAF (Ministry of Agriculture and Forest) (2005), "Development of environment-friendly boring revegetation measures in quarry area", Research Report, pp. 1-151.
  10. MOLIT (Ministry of Land, Infrastructure and Transport) and KICT (Korea Institute of Civil Engineering and Building Technology) (2018), Standard of construction estimate for civil, building and machine facility, Korea Institute of Civil Engineering and Building Technology, Goyang, pp. 407-414.
  11. Paone J., Madson D., Bruce W.E. (1969), "Drillability studies-laboratory percussive drilling". USBM RI 7300.
  12. Park, J.Y., Kim, J.H., Bae, S.H., Lee, J.S., Kim, T.G. (2007), "Analysis of geological engineering components and engineering characteristics of Jeoggagri conglomerate", Proceedings of the Korean Society of Economic and Environmental Geology Spring Conference, 25-27th, April, Kyeongju, pp. 292-295.
  13. Park, Y., Yoo, S.H., Kim, K.S. (2006), "DEM estimation of mechanical properties of conglomeratic rocks", Proceeding of the Korean Geotechical Society Spring Conference, 24-25th, March, Seoul, pp. 42-50.
  14. Tandanand S., Unger H.F. (1975), "Drillability determination-A drillability index of percussive drills". USBM RI 8073.
  15. Teale, R. (1965), "The concept of specific energy in rock drilling", International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, Vol. 2, No. 1, pp. 57-73. https://doi.org/10.1016/0148-9062(65)90022-7
  16. Thuro, K. (1997), "Drillability prediction: geological influences in hard rock drill and blast tunnelling", Geological Rundschau, Vol. 86, No. 2, pp. 426-438. https://doi.org/10.1007/s005310050151
  17. Thuro, K., Plinninger, R.J. (2003), "Hard rock tunnel boring, cutting, drilling and blasting: rock parameters for excavatability", In: Merwe JN, editor. Proceedings of the 10th International ISRM Congress on Technology Roadmap for Rock Mechanics, South African Institute of Mining and Metallurgy, pp. 1227-1233.