{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,13]],"date-time":"2026-05-13T04:21:05Z","timestamp":1778646065579,"version":"3.51.4"},"reference-count":25,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2023,2,12]],"date-time":"2023-02-12T00:00:00Z","timestamp":1676160000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Institute for Korea Spent Nuclear Fuel (iKSNF)","award":["No.2021M2E1A1085200"],"award-info":[{"award-number":["No.2021M2E1A1085200"]}]},{"name":"National Research Foundation of Korea (NRF)","award":["No.2021M2E1A1085200"],"award-info":[{"award-number":["No.2021M2E1A1085200"]}]},{"name":"Korea government (Ministry of Science and ICT, MSIT)","award":["No.2021M2E1A1085200"],"award-info":[{"award-number":["No.2021M2E1A1085200"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Materials"],"abstract":"<jats:p>In this study, a new digital technique for the analysis of the mechanical aperture and contact area of rock fractures under various normal stresses is proposed. The technique requires point cloud data of the upper and lower fracture surfaces, pressure film image data of the fracture, and normal deformation data of the fracture as input data. Three steps of algorithms were constructed using these input data: (1) a primary matching algorithm that considers the shape of the fracture surfaces; (2) a secondary matching algorithm that uses pressure film images; and (3) a translation algorithm that considers the normal deformation of a fracture. The applicability of the proposed technique was investigated using natural fracture specimens sampled at an underground research facility in Korea. In this process, the technique was validated through a comparison with the empirical equation suggested in a previous study. The proposed technique has the advantage of being able to analyze changes in the mechanical aperture and contact area under various normal stresses without multiple experiments. In addition, the change in the contact area on the fracture surface according to the normal stress can be analyzed in detail.<\/jats:p>","DOI":"10.3390\/ma16041538","type":"journal-article","created":{"date-parts":[[2023,2,13]],"date-time":"2023-02-13T01:48:56Z","timestamp":1676252936000},"page":"1538","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["A New Digital Analysis Technique for the Mechanical Aperture and Contact Area of Rock Fractures"],"prefix":"10.3390","volume":"16","author":[{"given":"Yong-Ki","family":"Lee","sequence":"first","affiliation":[{"name":"Disposal Performance Demonstration Research Division, Korea Atomic Energy Research Institute (KAERI), 111 Daedeok-daero, 989 Beon-gil, Yuseong-gu, Daejeon 34057, Republic of Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Chae-Soon","family":"Choi","sequence":"additional","affiliation":[{"name":"Disposal Performance Demonstration Research Division, Korea Atomic Energy Research Institute (KAERI), 111 Daedeok-daero, 989 Beon-gil, Yuseong-gu, Daejeon 34057, Republic of Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Seungbeom","family":"Choi","sequence":"additional","affiliation":[{"name":"Disposal Safety Evaluation Research Division, Korea Atomic Energy Research Institute (KAERI), 111 Daedeok-daero, 989 Beon-gil, Yuseong-gu, Daejeon 34057, Republic of Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Kyung-Woo","family":"Park","sequence":"additional","affiliation":[{"name":"Disposal Performance Demonstration Research Division, Korea Atomic Energy Research Institute (KAERI), 111 Daedeok-daero, 989 Beon-gil, Yuseong-gu, Daejeon 34057, Republic of Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2023,2,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"317","DOI":"10.1016\/S1365-1609(00)00079-4","article-title":"An improved model for hydromechanical coupling during shearing of rock joints","volume":"38","author":"Olsson","year":"2001","journal-title":"Int. J. Rock Mech. Min. Sci."},{"key":"ref_2","unstructured":"Gentier, S. (1986). Morphologie et Comportement Hydrom\u00e9canique d\u2019une Fracture Naturelle dans un Granite Sous Contrainte Normale. [Ph.D. Thesis, Univ. d\u2019Orl\u00e9ans]."},{"key":"ref_3","unstructured":"Gale, J. (July, January 29). Comparison of coupled fracture deformation and fluid flow models with direct measurements of fracture pore structure and stress-flow properties. Proceedings of the 28th US Symposium on Rock Mechanics, Tucson, AZ, USA."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"395","DOI":"10.1016\/0148-9062(95)00070-4","article-title":"Aperture measurements and flow experiments on a single natural fracture","volume":"33","author":"Hakami","year":"1996","journal-title":"Int. J. Rock Mech. Min. Sci. Geomech. Abstr."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"14-e1","DOI":"10.1016\/S1365-1609(97)00046-4","article-title":"The evolution of void spaces (permeability) in relation with rock joint shear behavior","volume":"34","author":"Archambault","year":"1997","journal-title":"Int. J. Rock Mech. Min. Sci."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"121","DOI":"10.1016\/j.ijrmms.2017.07.003","article-title":"Experimental study on the effect of fracture geometric characteristics on the permeability in deformable rough-walled fractures","volume":"98","author":"Chen","year":"2017","journal-title":"Int. J. Rock Mech. Min. Sci."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"149","DOI":"10.1007\/BF01583959","article-title":"Laboratory testing of the voids of a fracture","volume":"22","author":"Gentier","year":"1989","journal-title":"Rock Mech. Rock Eng."},{"key":"ref_8","unstructured":"Pyrak-Nolte, L., Myer, L., Cook, N., and Witherspoon, P. (September, January 30). Hydraulic and mechanical properties of natural fractures in low-permeability rock. Proceedings of the 6th ISRM Congress, Montreal, QC, Canada."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1051","DOI":"10.1016\/S0148-9062(98)00165-X","article-title":"Effect of shear displacement on the aperture and permeability of a rock fracture","volume":"35","author":"Yeo","year":"1998","journal-title":"Int. J. Rock Mech. Min. Sci."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1037","DOI":"10.1016\/S0148-9062(98)00164-8","article-title":"High Resolution, Non-Destructive Measurement and Characterization of Fracture Apertures","volume":"35","author":"Keller","year":"1998","journal-title":"Int. J. Rock Mech. Min. Sci."},{"key":"ref_11","unstructured":"Iwai, K. (1976). Fundamental Studies of Fluid Flow through a Single Fracture. [Ph.D. Thesis, University of California]."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"550","DOI":"10.1029\/GL014i005p00550","article-title":"Growth of contact area between rough surfaces under normal stress","volume":"14","author":"Stesky","year":"1987","journal-title":"Geophys. Res. Lett."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"254.e212","DOI":"10.1016\/S1365-1609(97)00164-0","article-title":"Variation in contact areas of rock joint surfaces as a function of scale","volume":"34","author":"Re","year":"1997","journal-title":"Int. J. Rock Mech. Min. Sci."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"81","DOI":"10.1016\/j.epsl.2009.02.005","article-title":"Direct measurement of contact area and stress dependence of anisotropic flow through rock fracture with heterogeneous aperture distribution","volume":"281","author":"Nemoto","year":"2009","journal-title":"Earth Planet. Sci. Lett."},{"key":"ref_15","unstructured":"Wang, F., and Kaunda, R.B. (2017, January 25\u201328). Artificial neural network modeling of contact electrical resistance profiles for detection of rock wall joint behavior. Proceedings of the 51st U.S. Rock Mechanics\/Geomechanics Symposium, San Francisco, CA, USA."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"105250","DOI":"10.1016\/j.enggeo.2019.105250","article-title":"Determination of shear failure regions of rock joints based on point clouds and image segmentation","volume":"260","author":"Ge","year":"2019","journal-title":"Eng. Geol."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"104044","DOI":"10.1016\/j.jsg.2020.104044","article-title":"Effect of contact surface area on frictional behaviour of dry and saturated rock joints","volume":"135","author":"Pirzada","year":"2020","journal-title":"J. Struct. Geol."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"249","DOI":"10.1016\/0148-9062(83)90595-8","article-title":"Fundamentals of rock joint deformation","volume":"20","author":"Bandis","year":"1983","journal-title":"Int. J. Rock Mech. Min. Sci. Geomech. Abstr."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"239","DOI":"10.1109\/34.121791","article-title":"A method for registration of 3-D shapes","volume":"14","author":"Besl","year":"1992","journal-title":"IEEE Trans. Pattern Anal. Mach. Intell."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"303","DOI":"10.1016\/0148-9062(79)90241-9","article-title":"Estimating joint roughness coefficients","volume":"16","author":"Tse","year":"1979","journal-title":"Int. J. Rock Mech. Min. Sci."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"3569","DOI":"10.1007\/s10064-021-02162-0","article-title":"Estimation of the appropriate sampling interval for rock joints roughness using laser scanning","volume":"80","author":"Ge","year":"2021","journal-title":"Bull. Eng. Geol. Environ."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"287","DOI":"10.1016\/0013-7952(73)90013-6","article-title":"Review of a new shear-strength criterion for rock joints","volume":"7","author":"Barton","year":"1973","journal-title":"Eng. Geol."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Choi, S., Jeon, B., Lee, S., and Jeon, S. (2019). Experimental study on hydromechanical behavior of an artificial rock joint with controlled roughness. Sustainability, 11.","DOI":"10.3390\/su11041014"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"105226","DOI":"10.1016\/j.ijrmms.2022.105226","article-title":"Is the widely used relation between mechanical and hydraulic apertures reliable? Viewpoints from laboratory experiments","volume":"159","author":"Nguyen","year":"2022","journal-title":"Int. J. Rock Mech. Min. Sci."},{"key":"ref_25","unstructured":"Snow, D.T. (1965). A Parallel Plate Model of Fractured Permeable Media. [Ph.D. Thesis, University of California]."}],"container-title":["Materials"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1996-1944\/16\/4\/1538\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T18:32:32Z","timestamp":1760121152000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1996-1944\/16\/4\/1538"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,2,12]]},"references-count":25,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2023,2]]}},"alternative-id":["ma16041538"],"URL":"https:\/\/doi.org\/10.3390\/ma16041538","relation":{},"ISSN":["1996-1944"],"issn-type":[{"value":"1996-1944","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,2,12]]}}}