A Fundamental Study on Shearing/Bonding Characteristics of Interface Between Rock Mass and Backfills in Mine Openings

Byung-Ryeol Kim, Hyeon-woo Lee, Young-Jin Kim, Kye-Hong Cho, Sung-Oong Choi

doi:10.7474/TUS.2021.31.6.623

All Issue

2021 Vol.31, Issue 6 Preview Page

Original Article

A Fundamental Study on Shearing/Bonding Characteristics of Interface Between Rock Mass and Backfills in Mine Openings 폐광산 채움재와 암반 경계부의 전단 및 접합특성에 관한 기초 연구

31 December 2021. pp. 623-646

PDF XML

Abstract

국내외적으로 전기화의 가속으로 인해 전력수요가 급증됨에 따라, 석탄화력발전소의 수요가 늘어나고 있다. 석탄화력발전소는 경제적으로 많은 이점이 있지만, 대기오염물질 증가, 발전회의 매립 처분에 의한 오염 유발 가능성 등의 환경적인 문제를 수반하고 있다. 특히, 발전부산물인 발전회의 경우에는 재활용률이 70%에 그치고 있으며, 나머지는 전량 매립되고 있다. 본 연구에서는 발전회의 재활용률을 증대시키고 지하에 위치하는 폐광산의 지반 안정성을 확보하기 위하여, 발전회를 폐광산 채움재로 이용하여 지하 폐광산의 채굴 공동을 충전하는 방안에 대한 기초연구를 수행하였다. 암반과 폐광산 채움재의 접합부에서 상호작용에 의한 충전 및 지반보강 효과를 분석하기 위하여, 다양한 거칠기를 갖는 절리면 모사 시료를 제작하여 접합강도 시험과 직접 전단시험을 수행하고 이에 대한 통계분석을 수행하여 절리면의 거칠기와 재령일에 따른 접합 및 전단거동 특성을 규명하였다. 또한 접합부 거동특성이 전산해석 기법을 이용한 지반안정성 분석에 미치는 영향을 검토하기 위하여 지하광산을 모델링하고 접합부 유무에 따른 거동특성을 비교하였다.

키워드

발전회

폐광산 채움재

암반-채움재 접합부

접합강도

전단 거동

As the demand for electric power increases with acceleration of electrification at home and abroad, the needs for coal-fired electrical power plant are accordingly increased. However, these coal-fired electrical power plants induce also many environmental problems such as increase of air pollutants, increase of possibility of land contamination by reclamation of coal ash, even though these power plants have a good economical efficiency. In case of a by-product of coal-fired electrical power plants, only 70% of them are recycled and the remaining 30% of by-product are fully buried in surrounding ground. Consequently, this study deals with coal ash backfilling mechanism in abandoned mine openings for the purposes of increasing the coal ash recycling rate as well as securing the mine area stability. In order to analyze the backfill and ground reinforcement by interaction between rock mass and backfills, the copying samples of discontinuous surface with different roughnesses were produced for bond strength tests and direct shear tests. And statistical analysis was also conducted to decide the characteristics of bond and shear behavior with joint roughness and their curing day. Numerical simulations were also analyzed for examining the effect of interface behavior on ground stability.

Keywords

Coal-ash

Backfilling in abandoned mine

Interface between rock mass and backfills

Bond strength

Shear behavior

References

ACI, 2005, Controlled Low-Strength Materials, ACI Committee 229, 1-15.

ASTM, 2017, Standard Test Method for Flow Consistency of Controlled Low Strength Material(CLSM), ASTM D6103/D6103M ASTM International, West Conshohocken, PA.

Bang, K.M. and Chon, H.T., 2004, A Study on the Ground Reinforcement against Land Subsidence in Abandoned Coal Mine Areas, Journal of the Korean Society of Mineral and Energy Resources Engineers, 41, 4, 319-326.

Barton, N. and Choubey, V., 1977, The Shear Strength of Rock Joints in Theory and Practice, Rock Mechanics, 10, 1-54. 10.1007/BF01261801

Cho, B.D., Kim, S.H. and Jeon, S.J., 2014, Assessment of Bond Characteristics between New and Old Concrete in Various Mixtures and Joint Conditions, J. of Korea Concrete Insitute, 26, 4, 507-515. 10.4334/JKCI.2014.26.4.507

Dawei, H., Oriol, P. and Albert A., 2020, Bond Strength Tests under Pure Shear and Tension between Masonry and Sprayed Mortar, MDPI, Materials, 13, 2183, 1-19. 10.3390/ma1309218332397464PMC7254242

Gratchev, I. and Kim, D.H., 2016, On the Reliability of The Strength Retention Ratio for Estimating the Strength of Weathered Rocks, Engineering Geology, 201, 1-5. 10.1016/j.enggeo.2015.12.005

Helinski, M., 2007, Mechanics of Mine Backfill, PhD Thesis, Western Australia University.

Helinski, M., Fahey, M. and Fourie, A., 2010, Behavior of Cemented Paste Backfill in Two Mine Stopes: Measurements and Modeling, J. of Geotechnical and Geoenvironmental Engineering, 137, 2, 171-182. 10.1061/(ASCE)GT.1943-5606.0000418

Itasca Consulting Group Inc., 2012, FLAC3D Manual, Version 5.0, Minneapolis, MN, USA.

Jang, H.S., Kang, S.S. and Jang, B.A., 2014, Determination of Joint Roughness Coefficients Using Roughness Parameters, Rock Mechanics and Rock Engineering, 47, 6, 2061-2073. 10.1007/s00603-013-0535-z

Kim, H.S., 2001, Experimental study on bond strength of interface between old concrete and new concrete, Daelim technical review, 12, 4-8.

KSA, 2010, Standard Test Method for Compressive Strength of Concrete, KS F 2405, Seoul, Korea.

KSA, 2017, Practice for mechanical mixing of hydraulic cement pastes and mortars of plastic consistency, KS L 5109, Seoul, Korea.

Kwon, M.H., Choi, S.O. and Kim, C.O, 2016, A Study on Stability Analysis of Large Underground Limestone Openings considering Excavation Damaged Zone, Tunnel and Underground Space, 26, 2, 131-142. 10.7474/TUS.2016.26.2.131

Lee, S.D. and Jeon, S.W., 2017, A Study on the Roughness Measurement for Joints in Rock Mass Using LiDAR, Tunnel and Underground Space, 27, 1, 58-68. 10.7474/TUS.2017.27.1.058

Liu, G., Li, L., Yang, X. and Guo, L., 2016, Numerical Analysis of Stress Distribution in Backfilled Stopes Considering Interfaces between the Backfill and Rock Walls, International Journal of Geomechanics, 17, 2, 1-9. 10.1061/(ASCE)GM.1943-5622.0000702

Masniyom, M., 2009, Systematic Selection and Application of Backfill in Underground Mines, PhD Thesis, Technischen University Bergakademie Freiberg.

Ministry of trade, industry and energy, 2015, 7th Basic Plan on Electricity Demand and Supply, Sejong, Korea.

Mishra, M. and Karanam, U., 2006, Grotechnical Characterization of Fly Ash Composites for Backfilling Mine Voids, Geotech. Geol. Eng., 24, 6, 1749-1765. 10.1007/s10706-006-6805-8

Moon, H.Y. and Yu, J.H., 2000, A Study on the Fundamental Properties of Mortar with Pig-iron Steel Slag Fine Aggregate, KSCE Journal of Civil Engineering, 1, 403-409.

Muralha, J., Grasselli, G., Tatone, B., Blumel, M., Chryssanthakis, P. & Jiang, Y., 2014, ISRM Suggested Method for Laboratory Determination of the Shear Strength of Rock Joints: Revised Version, Rock Mechanics and Rock Engineering, 47, 291-302. 10.1007/s00603-013-0519-z

Myers, N., 1962, Characterization of Surface Roughness, Wear, 5, 3, 182-189. 10.1016/0043-1648(62)90002-9

Park, B.Y. and Kwon, S.K., 2000, Current Status of the Characterization of the Rock Joint Surface, Tunnel and Underground Space, 10, 4, 566-579.

Sheshpari, M., 2015, A Review of Underground Mine Backfilling Methods with Emphasis on Cemented Paste Backfill, Electronic Journal of Geotechnical Engineering, 20, 13, 5183-5208.

Sivakugan, N., Veenstra, R. and Nahuleswaran, N., 2015, Underground Mine Backfilling in Australia Using Paste Fills and Hydraulic Fills, Int. J. of Geosynth. and Ground Eng., 1, 18, 1-7. 10.1007/s40891-015-0020-8

Tesarik, D., Seymour, J. and Yanske, T., 2009, Long-term Stability of a Backfilled Room-and-Pillar Test Section at the Buick Mine, Missouri, USA, International Journal of Rock Mechanics & Mining Sciences, 46, 1182-1196. 10.1016/j.ijrmms.2008.11.010

Walske, M., 2014, An Experimental Study of Cementing Paste Backfill, PhD Thesis, Western Australia University.

Yoo, J.C., Ji, S.W., Ahn, J.W., Kim, C.S. and Shin, H.Y., 2017, A Case Study of Mine Environmental Restoration using Coal Ash, J. of Korean Inst. of Resources Recycling, 26, 2, 80-88. 10.7844/kirr.2017.26.2.80

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 : 31
No :6
Pages :623-646
Received Date :2021. 12. 13
Revised Date :2021. 12. 17
Accepted Date : 2021. 12. 20
DOI :https://doi.org/10.7474/TUS.2021.31.6.623

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

All Issue