A method to downscale joint surface roughness and to create replica series using 3D printed molds

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Journal Title
Journal ISSN
Volume Title
Conference article in proceedings
Date
2017
Major/Subject
Mcode
Degree programme
Language
en
Pages
11
Series
ISRM 13th International Congress on Rock Mechanics, Montreal, May 10-13, 2015
Abstract
In order to determine the in-situ shear strength of rock joints, large scale testing is required. However, this is both expensive and difficult to execute. One possible method to overcome this may be to use photogrammetry to capture large joint surface roughness in-situ and downscale it to replica samples, which could be sheared in laboratory. In this paper, as a first part in such a method, a technique to digitize surface roughness and to produce replica samples for laboratory shear testing from a larger joint sample are presented. First, a thin granitic rock slice with dimensions of 1.75 m x 0.95 m of granitic intact rock was chosen for the study. The joint surface is fresh and created through tensile induced splitting. The large joint sample is digitized using photogrammetry. Then, one full-scale 1.7 m x 0.6 m geometry is cropped from the digitized joint geometry and then subsamples at 10x, 7.5x, 5x, 2.5x and 1x scales. All sub-geometries are scaled down digitally to produce 0.17 m by 0.06 m geometries. The geometries are used to make casting molds both positive and negative to produce samples with perfect matedness. The casting molds are 3D printed in polylactic acid plastic and C60/75 concrete is cast to produce a replica series. In addition to the creation of this replica series, two pilot replicas are also tested using a portable shear box with a 0.5 MPa normal pressure. The results from the pilot rounds are presented and discussed. Finally, suggestions for future research are given.
Description
VK: T20703
Keywords
Joint, Crack, Fracture, Photogrammetry, 3D printing, Replica, Concrete, Shear Box
Other note
Citation
Uotinen , L , Korpi , E , Hartikainen , A , Yorke , R , Antikainen , J , Johansson , F & Rinne , M 2017 , A method to downscale joint surface roughness and to create replica series using 3D printed molds . in ISRM 13th International Congress on Rock Mechanics, Montreal, May 10-13, 2015 . Canadian Institute of Mining, Metallurgy and Petroleum , ISRM International Congress on Rock Mechanics , Montreal , Canada , 10/05/2015 .