Review on Rock-Mechanical Models and Numerical Analyses for the Evaluation on Mechanical Stability of Rockmass as a Natural Barriar

Myung Kyu Song; Tae Young Ko; Sean S. W. Lee; Kunchai Lee; Byungchan Kim; Jaehoon Jung; Yongjin Shin

doi:10.7474/TUS.2023.33.6.445

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2023 Vol.33, Issue 6 Preview Page Next Page

Technical Note

Review on Rock-Mechanical Models and Numerical Analyses for the Evaluation on Mechanical Stability of Rockmass as a Natural Barriar 천연방벽 장기 안정성 평가를 위한 암반역학적 모델 고찰 및 수치해석 검토

31 December 2023. pp. 445-471

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Abstract

Long-term safety over millennia is the top priority consideration in the construction of disposal sites. However, ensuring the mechanical stability of deep geological repositories for spent fuel, a.k.a. radwaste, disposal during construction and operation is also crucial for safe operation of the repository. Imposing restrictions or limitations on tunnel support and lining materials such as shotcrete, concrete, grouting, which might compromise the sealing performance of backfill and buffer materials which are essential elements for the long-term safety of disposal sites, presents a highly challenging task for rock engineers and tunnelling experts. In this study, as part of an extensive exploration to aid in the proper selection of disposal sites, the anticipation of constructing a deep geological repository at a depth of 500 meters in an unknown state has been carried out. Through a review of 2D and 3D numerical analyses, the study aimed to explore the range of properties that ensure stability. Preliminary findings identified the potential range of rock properties that secure the stability of central and disposal tunnels, while the stability of the vertical tunnel network was confirmed through 3D analysis, outlining fundamental rock conditions necessary for the construction of disposal sites.

Keywords

Deep geological dispososal facility

Spent nuclear fuel

Tunnel stability

Unsupported tunnel

Rockmass properties

수만년 이상의 기간동안의 장기 안전성을 확보하는 것이 처분장 건설에서의 최우선 조건이나, 건설 및 운영중 대심도 지하 사용후핵연료 처분장의 역학적 안정성 확보 역시 안전한 터널 공사 및 운영을 위해 필수적인 요소이다. 처분장의 장기 안전성에 중요한 요소인 벤트나이트 충전재 및 완충재의 차폐 성능을 저감시킬 가능성이 있는 숏크리트, 콘크리트, 그라우팅 등의 터널 지보공 및 차수공을 금지 내지는 제한 하는 조건은 암반공학자 및 터널 기술자에게 매우 도전적인 과제로 판단된다. 본 연구에서는 처분장 부지 선정과정에서 올바른 처분장의 선정에 도움이 될 수 있는 대심도에 건설할 것으로 예상되는 처분장의 터널 네트워크, 처분 터널 및 처분공의 역학적 안정성을 확보하기 위한 제반 조건의 광범위한 탐색의 일환으로 지하 500 m 심도의 처분장을 무지보 상태로 건설할 경우 2차원 및 3차원 수치해석 검토를 통해 안정성의 확보 가능한 물성 범위를 탐색하고자 하였다. 예비 연구결과 처분장의 중앙터널과 처분터널 안정성 확보 가능 암반물성의 범위를 파악하였으며, 3차원 해석을 통해 수직구 주변 터널 네트워크의 안정성을 확인하여 처분장 건설을 위한 기초적인 암반 조건이 파악된 것으로 판단된다.

키워드

심층처분시설

사용후핵연료

터널 안정성

무지보 터널

암반물성

References

Andersson, J., Strom, A., Svemar, C., Almen, K.E., and Ericsson, L.O., 2000, What requirements does the KBS-3 repository make on the host rock, Geoscientific Suitability Indicators and Criteria for Siting And Site Evaluation.

Bae, S.H., Jeon, S.W., Choi, Y.K., and Kim, H.S., 2002, Study on Characteristics of In-situ Rock Stress State in Mountainous Region by Hydraulic Fracturing Method, J. of Korean Tunn. Undergr. Sp. Assoc., 4(1), 57-70.

Carlsson, A., and Christiansson, R., 1986, Rock stresses and geological structures in the Forsmark area, In ISRM International Symposium, OnePetro.

Castro, L.A.M., McCreath, D.R., and Oliver, P., 1996, Rockmass damage initiation around the Sudbury neutrino observatory cavern, In 2nd North American Rock Mechanics Symposium, OnePetro.

Diederichs, M.S. and Kaiser, P.K., 1999, Tensile strength and abutment relaxation as failure control mechanisms in underground excavations, International Journal of Rock Mechanics and Mining Sciences, 36(1), 69-96. 10.1016/S0148-9062(98)00179-X

Diederichs, M.S., 2003, Rock fracture and collapse under low conﬁnement conditions. Rock Mech. Rock Eng., 35, 339-381. 10.1007/s00603-003-0015-y

Hajiabdolmajid, V., Martin, C.D., and Kaiser, P.K., 2000, Modelling Brittle Failure of Rock, Paper presented at the 4th North American Rock Mechanics Symposium, NARMS 2000, A.A. Balkema, Seattle, Washington, 991-998.

Hedley, D.G.F. and Grant, F., 1972, Stope-and-pillar design for the Elliot Lake Uranium Mines, Bull. Can. Inst. Min. Metall., 65, 37-44.

Hedley, D.G.F., Roxburgh, J.W., Muppalaneni, S.N., 1984, A case history of rockbursts at Elliot Lake. In: Proceedings of 2nd International Conference on Stability in Underground Mining, Lexington. New York: American Institute of Mining, Metallurgical and Petroleum Engineers, Inc., 210-34.

Hoek, E. and Brown, E.T., 1980, Underground excavations in rock, Inst. Mining and Metallurgy, London, 156.

Hudson, J.A., Brown, E.T., and Fairhurst, C., 1972, Shape of the complete stress-strain curve for rock, In Proc. 13th U.S. Symp. on Rock Mechanics, Urbana, (Ed. E. Cording), American Society of Civil Engineers, New York, 773-795.

KAERI, 2008, Current R&D Status on High-Level Rdioactive Waste Disposal in Selected Countries, AR-821.

Lee, C.S., Cho, W.J., Lee, J.W., and Kim, G.Y., 2019, Numerical Analysis of Coupled Thermo-Hydro-Mechanical (THM) Behavior at Korean Reference Disposal System (KRS) Using TOUGH2-MP/FLAC3D Simulator, J. Nuclear Fuel Cycle & Waste Technology, 17(2), 183-202. 10.7733/jnfcwt.2019.17.2.183

Lunder, P.J. and Pakalnis, R.C., 1997, Determination of the strength of hard-rock mine pillars, CIM bulletin, 90(1013), 51-55.

Martin, C.D. and Chandler, N.A., 1994, December, The progressive fracture of Lac du Bonnet granite, International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 31(6), 643-659, Pergamon. 10.1016/0148-9062(94)90005-1

Martin, C.D. and Maybee, W.G., 2000, The strength of hard-rock pillars.International Journal of Rock Mechanics and Mining Sciences, 37(8), 1239-1246. 10.1016/S1365-1609(00)00032-0

Martin, C.D., Christiansson, R., and Söderhäll, J., (2001), Rock stability considerations for siting and constructing a KBS-3 Based on experiences from Äspö HRL, AECL's URL, tunnelling and miningrepository, Technical Report TR-01-38, SKB

Martin, C.D., Kaiser, P.K., and McCreath, D.R., 1999b, Hoek-Brown parameters for predicting the depth of brittle failure around tunnels, Canadian Geotechnical Journal, 36(1), 136-151. 10.1139/t98-072

Martin, C.D., Kaiser, P.K., Tannant, D.D., and Yazici, S., 1999a, Stress path and instability around mine openings, In 9th ISRM Congress, 1, 311-315.

Ohta, M.M. and Chandler, N.A., 1997, AECL's underground research laboratory: technical achievements and lessons learned. Canada: N. p., Web.

Olsson, O., 1996, ZEDEX-A Study of the Zone of Excavation Disturbance for Blasted and Bored Tunnels, SKB International Cooperation Report., 96-3.

Pettitt, W. and Young, P., 2000, Analysis of the in situ principal stress field at the HRL using acoustic emission data, Prototype Experiment, Report IPR-01, 9.

Posiva Oy., 2013, WR 2012-66 Facility Description 2012. Summary Report of Encapsulation Plan and Disposal Facility Designs.

Pritchard, C.J. and Hedley, D.G.F., 1993, Progressive pillar failure and rockbursting at Denison Mine, In Proc. 3rd Int. Symp. on Rockbursts and Seismicity in Mines, Rotterdam, A. A. Balkema, Kingston (Ed. R. P. Young), 111-116.

Read, R.S. and Chandler, N.A., 1997, Minimizing excavation damage through tunnel design in adverse stress conditions, In Proceedings of the International Tunnelling Association World Tunnel Congress, Vienna, 1, 23-28.

Siren, T., Kantia, P., and Rinne, M., 2015, Considerations and observations of stress-induced and construction-induced excavation damage zone in crystalline rock. International Journal of Rock Mechanics and Mining Sciences, 73, 165-174. 10.1016/j.ijrmms.2014.11.001

SKB, 2010, Design, construction and initial state of the underground openings, TR-10-18.

Soder, P. and Krauland, N., 1990, Determination of pillar strength by full scale pillar tests in the Laisvall mine, In Plenary scientific session of the International Bureau of Strata Mechanics, world mining congress, 39-59.

Swan, G., 1985, Strength distribution and potential for multiplepillar collapse. Divisional Report MRL 85-127 (TR), CANMET.Energy Mines and Resources, Canada.

Synn, J.H., Park, C., and Lee, B.J., 2013, Regional Distribution Pattern and Geo-historical Transition of In-situ Stress Fields in the Korean Peninsula, Tunn. Undergr. Space, 23(6), 457-469. 10.7474/TUS.2013.23.6.457

Information

Publisher :Korean Society for Rock Mechanics and Rock Engineering
Publisher(Ko) :한국암반공학회
Journal Title :Tunnel and Underground Space
Journal Title(Ko) :터널과 지하공간
Volume : 33
No :6
Pages :445-471
Received Date : 2023-11-23
Revised Date : 2023-12-26
Accepted Date : 2023-12-26
DOI :https://doi.org/10.7474/TUS.2023.33.6.445

Tunnel and Underground SpaceISSN:1225-1275(Print) 2287-1748(Online)한국암반공학회

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